Tue·Nov 30, 2021Tuesday·November 30, 2021

1. 01*

   Neutrino flavor mixing with moments

   McKenzie Myers🇺🇸 · Theo Cooper🇺🇸 · MacKenzie Warren🇷🇺 · Jim Kneller🇺🇸 · Gail McLaughlin🇺🇸 · Sherwood Richers🇺🇸 · Evan Grohs🇺🇸 · Carla Frohlich🇺🇸

   The successful transition from core-collapse supernova simulations using classical neutrino transport to simulations using quantum neutrino transport will require the development of methods for calculating neutrino flavor transformations that mitigate the computational expense. One potential approach is the use of angular moments of the neutrino field, which has the added appeal that there already exist simulation codes which make use of moments for classical neutrino transport. Evolution equations for quantum moments based on the quantum kinetic equations can be straightforwardly generalized from the evolution of classical moments based on the Boltzmann equation. We present an efficient implementation of neutrino transformation using quantum angular moments in the free streaming, spherically symmetric bulb model. We compare the results against analytic solutions and the results from more exact multi-angle neutrino flavor evolution calculations. We find that our moment-based methods employing scalar closures predict, with good accuracy, the onset of collective flavor transformations seen in the multi-angle results. However in some situations they overestimate the coherence of neutrinos traveling along different trajectories. More sophisticated quantum closures may improve the agreement between the inexpensive moment-based methods and the multi-angle approach.

   hep-phastro-ph.HEastro-ph.SRnucl-thPRD(2022)·20 citations
2. 02*

   Flavour alignment of New Physics in light of the $(g-2{)}_{\mu }$ anomaly

   Gino Isidori🇨🇭 · Julie Pagès🇨🇭 · Felix Wilsch🇨🇭

   We investigate the flavour alignment conditions that New Physics (NP) models need to satisfy in order to address the $(g-2{)}_{\mu }$ anomaly and, at the same time, be consistent with the tight bounds from $\mu \to e\gamma$ and $\tau \to \mu \gamma$. We analyse the problem in general terms within the SMEFT, considering the renormalisation group evolution of all the operators involved. We show that semileptonic four-fermion operators, which are likely to generate a sizeable contribution to the $(g-2{)}_{\mu }$ anomaly, need to be tightly aligned to the lepton Yukawa couplings and the dipole operators in flavour space. While this tuning can be achieved in specific NP constructions, employing particular dynamical assumptions and/or flavour symmetry hypotheses, it is problematic in a wide class of models with broken flavour symmetries, such as those proposed to address both charged- and neutral-current $B$ anomalies. We quantify this tension both in general terms, and in the context of explicit NP constructions.

   hep-phJHEP(2022)·26 citations
3. 03*

   Splitting rates in QCD plasmas from a non-perturbative determination of the momentum broadening kernel $C(q_{\perp })$

   Soeren Schlichting🇩🇪 · Ismail Soudi🇺🇸

   We exploit a recent non-perturbative determination of the momentum broadening kernel $C(b_{\perp })$ in impact parameter space \cite{Moore:2021jwe}, to determine the momentum space broadening kernel $C(q_{\perp })$ in high-temperature QCD plasmas. We show how to use the non-pertubatively determined kernel $C(q_{\perp })$ to compute the medium-induced splitting rates in a QCD plasma of finite size. We compare the resulting in-medium splitting rates to the results obtained with leading-order and next-to-leading order perturbative determinations of $C(q_{\perp })$, as well as with various approximations of the splitting employed in the literature. Generally, we find that the differences in the splitting rates due to the momentum broadening kernel are larger than the errors associated with approximations of the splitting rate.

   hep-phnucl-thPRD(2022)·36 citations
4. 04*

   Hypermassive quark cores

   Luiz L. Lopes🇧🇷 · Carline Biesdorf🇧🇷 · Débora P. Menezes🇧🇷

   Using a quantum hadrodynamics (QHD) and MIT based models we construct hybrid stars within the Maxwell criteria of hadron-quark phase transition. We are able to produce a hybrid star with maximum mass of 2.15$M_{\odot }$. Furthermore, a 2.03$M_{\odot }$ star with a quark core corresponding to more than $80\%$ of both, its total mass and radius, is also possible.

   hep-phastro-ph.HEnucl-thMNRAS(2022)·29 citations
5. 05*

   Predicted $\Lambda \bar{\Lambda }$ and ${\Xi }^{-}{\bar{\Xi }}^{+}$ decay modes of the charmoniumlike $Y(4230)$

   Ri-Qing Qian🇨🇳 · Qi Huang🇨🇳 · Xiang Liu🇨🇳

   In this work, we predict the light hadronic decay channels $Y(4230)\to \Lambda \bar{\Lambda }$ and ${\Xi }^{-}{\bar{\Xi }}^{+}$ when treating the $Y(4230)$ as a vector charmonium state. By the hadronic loop mechanism, the branching ratios of the $Y(4230)\to \Lambda \bar{\Lambda }$ and ${\Xi }^{-}{\bar{\Xi }}^{+}$ processes are calculated. In addition, we discuss the possibility of carrying out the search for the signal of the $Y(4230)$ through $\Lambda \bar{\Lambda }$ and ${\Xi }^{-}{\bar{\Xi }}^{+}$ channels from the $e^{+}{e}^{-}$ annihilation. Assuming $Y(4230)$ exist in $\Lambda \bar{\Lambda }$ and ${\Xi }^{-}{\bar{\Xi }}^{+}$ channel, we also present the time-like electromagnetic form factors (EMFFs) at $\sqrt{s}=m_{Y(4230)}$.

   hep-phhep-exPLB(2022)·22 citations
6. 06*

   Signatures of linear Breit-Wheeler pair production in polarized $\gamma \gamma$ collisions

   Qian Zhao🇨🇳 · Liang Tang🇨🇳 · Feng Wan🇨🇳 · Bo-Chao Liu🇨🇳 · Ruo-Yu Liu🇨🇳 · Rui-Zhi Yang🇨🇳 · Jin-Qing Yu🇨🇳 · Xue-Guang Ren🇨🇳 · Zhong-Feng Xu🇨🇳 · Yong-Tao Zhao🇨🇳 · Yong-Sheng Huang🇨🇳 · Jian-Xing Li🇨🇳

   Laser-driven brilliant controllable polarized $\gamma$-photon sources open the way for designing compact $\gamma \gamma$ collider, which enable the large yield of linear Breit-Wheeler (LBW) pairs in a single shot and thus provide an opportunity for the investigation of polarized LBW process. In this work we investigate the polarization characteristics of LBW pair production via our developed spin-resolved binary collision simulation method. Polarization of $\gamma$-photons modifies the kinematics of scattering particles and induces the correlated energy-angle shift of LBW pairs, and the latter's polarization characteristic depends on the helicity configures of scattering particles. Our method confirms that the polarized $\gamma \gamma$ collider with an asymmetric setup can be performed with currently achievable laser facilities to produce abundant polarized LBW pairs, fulfilling the detection power of polarimetries. The precise knowledge of polarized LBW process is in favor of the calibration and monitor of polarized $\gamma \gamma$ collider, and could enhance the opacity of $\gamma$-photons in high-energy astrophysical objects to exacerbate the inconsistency between some observations and standard models.

   hep-phPRD(2022)·18 citations
7. 07*

   The Masses of Gauge Bosons in $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_{Y^{\prime }}\times U(1{)}_{B-L}$ gauge model

   M. C. Rodriguez🇧🇷

   We will present within the context of the supersymmetric models with $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_{Y^{\prime }}\times U(1{)}_{B-L}$ gauge symmetry an explanation for the new data on the $W$-boson mass recently presented by the CDF collaboration. We will also study the neutral boson sector of this model.

   hep-ph1 citation
8. 08*

   Mass of $1^{-+}$ four-quark--hybrid mixed states

   Shuang-Hong Li🇨🇳 · Ze-Sheng Chen🇨🇳 · Hong-Ying Jin🇨🇳 · Wei Chen🇨🇳

   We calculate the masses of $J^{PC}=1^{-+}$ light exotic mesons by QCD sum rules; the masses are extracted from four-quark--hybrid mixing correlation functions. We construct several $1^{-+}$ four-quark currents and hybrid currents, and get two masses around $1.2\text{-}1.4\text{GeV}$ and $1.45\text{-}1.67\text{GeV}$; they can be identified as ${\pi }_1(1400)$ and ${\pi }_1(1600)$.

   hep-phPRD(2022)·16 citations
9. 09*

   Is BFKL factorization valid for Mueller-Tang jets?

   Dimitri Colferai🇮🇹

   The perturbative QCD description of high-energy hadroproduction of two hard jets separated by a large rapidity gap void of emission (also called Mueller-Tang jets) is based on a factorization formula of BFKL type that represents exchanges of colour-singlet objects among the external particles. This formula resums to all perturbative orders a certain class of Feynman diagrams that are supposed to dominate the cross-section in the Regge limit. However, the explicit calculations at next-to-leading logarithmic order questions the validity of such factorization when an IR safe jet algorithm is used to reconstruct jets. We show the origin of such violation of factorization, and quantify its impact for LHC phenomenology. In this connection, we estimate the impact of other contributions to the cross-section that are not included in the Mueller-Tang factorization formula -- colour non-singlet exchanges -- that, at low rapidity separation, compete with the singlet ones.

   hep-ph0 citations
10. 10*

    Production of the $B_c$ meson at the CEPC

    Ze-Yang Zhang🇨🇳 · Xu-Chang Zheng🇨🇳 · Xing-Gang Wu🇨🇳

    In this paper, we make a detailed study on the production of the $B_c$, $B_c^{\ast }$, $B_c(2{}^1{S}_0)$, and $B_c^{\ast }(2{}^3{S}_1)$ mesons via the three planned running modes ($Z$, $W$, and $H$) at the future Circular Electron-Positron Collider (CEPC). The fragmentation-function and full nonrelativistic QCD approaches are adopted to calculate the production cross sections. Considering the excited states shall decay to the ground $B_c$ state (e.g. $1^1{S}_0$-state) with almost $100\%$ probability, our numerical results show that up to next-to-leading order QCD corrections, there are about $1.4\times 10^8$ $B_c$ events to be accumulated via the $Z$ mode ($\sqrt{s}=m_{{}_Z}$) of the CEPC, but only about $1.6\times 10^4$ and $1.1\times 10^4$ $B_c$ events to be accumulated via the $W$ ($\sqrt{s}=160\mathrm{GeV}$) and $H$ ($\sqrt{s}=240\mathrm{GeV}$) modes, respectively. Since the $Z$ mode is the best mode among the three planned modes of the CEPC for studying the production of the $B_c$, $B_c^{\ast }$, $B_c(2{}^1{S}_0)$, and $B_c^{\ast }(2{}^3{S}_1)$ mesons and the differential distributions of these mesons may be measured precisely at this mode, we further present the differential cross sections $d\sigma /(dzd\cos \theta )$ and $d\sigma /dz$ via the $Z$ mode of the CEPC.

    hep-phEPJC(2022)·10 citations
11. 11*

    The lineshape of the compact fully heavy tetraquark

    Zejian Zhuang🇨🇳 · Ying Zhang🇨🇳 · Yuanzhuo Ma🇨🇳 · Qian Wang🇨🇳

    Hadrons and their distributions are the most direct observables in experiment, which would shed light on the non-perturbative mystery of quantum chromodynamics (QCD). As the result, any new hadron will challenge our current knowlege on the one hand, and provide additional inputs on the other hand. The fully heavy $cc\bar{c}\bar{c}$ system observed by LHCb recently opens a new era for hadron physics. We first extract the internal structure of the fully heavy tetraquarks directly from the experimental data, within the compact tetraquark picture. By fitting to the di-$J/\psi$ lineshape, we find that the $X(6900)$ is only cusp effect from the $J/\psi \psi (3770)$ channel. In addition, there is also a cusp slightly below $6.8\mathrm{GeV}$ stemming from the $J/\psi {\psi }^{\prime }$ channel. The two $0^{++}$ tetraquarks behave as two resonances above the di-${\eta }_c$ and di-$J/\psi$ threshold, respectively. The $2^{++}$ state is a bound state below the di-$J/\psi$ threshold. Furthermore, we find that the $X_{0^{++}}(6035)$ shows a significant structure in the di-${\eta }_c$ lineshape even after the coupled channel effect. This is an unique feature which can distinguish compact $cc\bar{c}\bar{c}$ tetraquark from the loosely hadronic molecules.

    hep-phPRD(2022)·33 citations
12. 12*

    Study of heavy quark conserving weak decays in the quark model

    Peng-Yu Niu🇨🇳 · Qian Wang🇨🇳 · Qiang Zhao🇨🇳

    Within the framework of a constituent quark model, we investigate the heavy quark conserving weak decays of ${\Xi }_c$ and ${\Xi }_b$. This process involves elementary transitions of $us\to du$ or $s\to ud\bar{u}$ with the heavy quark as a spectator, while for the charmed baryon in the initial state it can also occur via $cs\to dc$ to conserve the heavy quark flavor in the weak decays. It shows that the heavy quark symmetry (HQS) plays an essential role in the processes where the heavy quark acts as a spectator. For the ${\Xi }_c$ decays, the dominance of the pole terms in the parity-conserving transitions is evident. This can naturally explain the sizeable branching ratio for ${\Xi }_c^0\to {\Lambda }_c{\pi }^{-}$ as recently reported by LHCb. The same mechanism predicts a large branching ratio for ${\Xi }_c^{+}\to {\Lambda }_c{\pi }^0$. In contrast, the decays of ${\Xi }_b$ will only go through the parity-violating processes because of the HQS. In addition, the branching ratios of the ${\Xi }_c^{+}\to {\Lambda }_c{\pi }^0$ and ${\Xi }_b^0\to {\Lambda }_b{\pi }^0$ processes are also predicted for the further experimental measurement.

    hep-phPLB(2022)·29 citations
13. 13*

    Far from equilibrium Chiral Magnetic Effect in Strong Magnetic Fields from Holography

    Sebastian Grieninger🇪🇸 · Sergio Morales-Tejera🇪🇸

    We study the real time evolution of the chiral magnetic effect out-of-equilibrium in strongly coupled anomalous field theories. We match the parameters of our model to QCD parameters and draw lessons of possible relevance for the realization of the chiral magnetic effect in heavy ion collisions. In particular, we find an equilibration time of about $\sim 0.35$ fm/c in presence of the chiral anomaly for plasma temperatures of order $T\sim 300-400$ MeV.

    hep-phhep-thnucl-exnucl-thEPJ Web Conf.(2022)·3 citations
14. 14*

    Master integrals for mixed QCD-QED corrections to charged-current Drell-Yan production of a massive charged lepton

    Ming-Ming Long🇨🇳 · Ren-You Zhang🇨🇳 · Wen-Gan Ma🇨🇳 · Yi Jiang🇨🇳 · Liang Han🇨🇳 · Zhe Li🇨🇳 · Shuai-Shuai Wang🇨🇳

    The master integrals for the mixed QCD-QED two-loop virtual corrections to the charged-current Drell-Yan process $q{\bar{q}}^{\prime }\to \ell \nu$ are computed analytically by using the differential equation method. A suitable choice of master integrals makes it successful to cast the differential equation system into the canonical form. We keep the dependence on charged lepton mass in the building of differential equations and then expand the system against the ratio of small charged lepton mass to large $W$-boson mass. In such a way the final results will contain large logarithms of the form $\log (m_{\ell }^2/m_W^2)$. Finally, all the canonical master integrals are given as Taylor series around $d=4$ spacetime dimensions up to order four, with coefficients expressed in terms of Goncharov polylogarithms up to weight four.

    hep-phJHEP(2022)·5 citations
15. 15*

    Two-loop master integrals for the single top production associated with $W$ boson

    Ming-Ming Long🇨🇳 · Ren-You Zhang🇨🇳 · Wen-Gan Ma🇨🇳 · Yi Jiang🇨🇳 · Liang Han🇨🇳 · Zhe Li🇨🇳 · Shuai-Shuai Wang🇨🇳

    The $tW$ associated production has the second-largest cross section among three single top production channels. A complete study of NNLO QCD corrections to $tW$ production is still missing in literature. We present the calculation of part of the requisite two-loop master integrals for the process $b+g\to t+W$ at NNLO QCD. It turns out that the 80 master integrals in two families, involving up to three massive internal lines, can be expressed by Goncharov polylogarithms. The canonical differential equations that these integrals obey contain at most three square roots. By separating the canonical master integrals into groups according to their dependences on roots, we succeed in achieving optimization of final expressions, which are validated by independent numerical checks.

    hep-ph12 citations
16. 16*

    Two-photon transitions of charmonia on the light front

    Yang Li🇨🇳 · Meijian Li🇫🇮 · James P. Vary🇺🇸

    We investigate the two-photon transitions $H_{c\bar{c}}\to {\gamma }^{\ast }\gamma$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography and one-gluon exchange interaction within the basis light-front quantization approach. We compute the two-photon transition form factors as well as the two-photon decay widths for S- and P-wave charmonia, ${\eta }_c$ and ${\chi }_{cJ}$ and their excitations. Without introducing any free parameters, our predictions are in good agreement with the recent experimental measurements by BaBar and Belle, shedding light on the relativistic nature of charmonium.

    hep-phnucl-thPRD(2022)·27 citations
17. 17*

    Neutrino Oscillation parameter determination at INO-ICAL using track and hit information from GEANT

    Jaydeep Datta🇮🇳 · Bana Singh🇮🇳 · S. Uma Sankar🇮🇳

    We study the capability of INO-ICAL to determine the atmospheric neutrino oscillation parameters $|\Delta m_{31}^2|$ and ${\sin }^2{\theta }_{23}$. We do not use any generator level information. Instead, we process the generated atmospheric neutrino events through GEANT4 simulation of the detector and the event reconstruction framework. Among the outputs of this framework, only the momentum and direction of the longest track were used in a previous study by other authors. In this study, in addition to these variables, we consider a third variable based on additional hits, which arise due to hadrons in the event. We show that the inclusion of the this variable leads to a 30% reduction in the uncertainties of $|\Delta m_{31}^2|$ for a 5-year run of ICAL. We find that doubling the exposure time leads to a 30% reduction in the uncertainties of both $|\Delta m_{31}^2|$ and ${\sin }^2{\theta }_{23}$.

    hep-phhep-exJINST(2022)·1 citation
18. 18*

    Custodial symmetry, Georgi-Machacek model, and other scalar extensions

    Anirban Kundu🇮🇳 · Poulami Mondal🇮🇳 · Palash B. Pal🇮🇳

    In an SU(2) gauge theory, if the gauge bosons turn out to be degenerate after spontaneous symmetry breaking, obviously these mass terms are invariant under a global SU(2) symmetry that is unbroken. The pure gauge terms are also invariant under this symmetry. This symmetry is called the {\em custodial symmetry} (CS). In $\mathrm{SU}(2)\times \mathrm{U}(1)$ gauge theories, CS implies a mass relation between the $W$ and the $Z$ bosons. The Standard Model (SM), as well as various extensions of it in the scalar sector, possess such a symmetry. In this paper, we critically examine the notion of CS and show that there may be three different classes of CS, depending on the gauge couplings and self-couplings of the scalars. Among old models that preserve CS, we discuss the Two-Higgs Doublet Model and the one doublet plus two triplet model by Georgi and Machacek. We show that for two-triplet extensions, the Georgi-Machacek model is not the most general possibility with CS. Rather, we find, as the most general extension, a new model with more parameters and hence a richer phenomenology. Some of the consequences of this new model have also been discussed.

    hep-phPRD(2022)·23 citations
19. 19*

    The gluon Regge trajectory at three loops from planar Yang-Mills theory

    Vittorio Del Duca🇨🇭 · Robin Marzucca🇩🇰 · Bram Verbeek🇸🇪

    We compute the three-loop leading-colour corrections to the Yang-Mills Regge trajectory and gluon impact factor. Conjecturing that, in analogy with $\mathcal{N}=4$ super Yang-Mills (SYM), in a suitable scheme $N_c$-subleading terms are absent from the three-loop Regge trajectory, we understand our result as the first computation of the pure gauge, or $n_f=0$, part of the QCD three-loop Regge trajectory. The results are presented both for the bare and renormalised amplitudes and are consistent with predictions from infrared factorisation along with reproducing known results in planar $\mathcal{N}=4$ SYM through a maximal weight truncation. We also include the dependence on a Regge factorisation scale to facilitate future applications in BFKL theory at next-to-next-to leading logarithmic accuracy.

    hep-phhep-thJHEP(2022)·33 citations
20. 20*

    Analyzing polarized boosted top from stop decay at high luminosity and high energy LHC

    Jayita Lahiri🇮🇳

    Measuring top polarization is extremely important in understanding any new physics that couples to top quark. Here, we take up the task of extracting polarization of top quark coming from TeV-scale stop decay at the upgraded high luminosity and high energy LHC. We focus on the scenario where the two tops from the stop decay lead to semi-leptonic final state. We take into account all relevant backgrounds and put kinematical cuts to suppress them. We arrive at a signal region where the desired signal can be observed with reasonable significance. Next, we examine, in such signal regions, how well top polarization can be measured. For that we have calculated the degree with which left- and right-handed top quarks can be separated from each other, in terms of $P$-values. We have also performed a comparative study between various centre-of-mass energies and integrated luminosities in terms of their reach in probing top polarization from stop decay.

    hep-ph0 citations
21. 21*

    Handedness Correlation from Quark Polarization

    W. Yang🇨🇳

    Jet handedness as a measure of quark and/or gluon polarizations has been proposed for nearly 30 years. It was demonstrated by measuring the correlation of jet handedness in the electron positron annihilation process. Once parameters are determined, the method could be used to measure quark and/or gluon polarizations in other experiments. The reported data provided evidence for the jet handedness and handedness correlation. However, the jet handedness correlation measured in the electron positron annihilation process from the opposite jets contradicts theoretical prediction by a sign. In order to explain this, we present a chromo-hydrogen-like model in this paper. According to calculations, both jet handedness and handedness correlation depend on not only the polarization of the fragmenting valence quark but also the polarization of the sea quark. It is the appearance of the sea quark polarization that can solve the contradiction. In other words, measurements of jet handedness and handedness correlation can be used to determine the sea quark polarization.

    hep-phNPA(2022)·0 citations
22. 22*

    Non-minimal Lorentz invariance violation in light of muon anomalous magnetic moment and long-baseline neutrino oscillation data

    Hai-Xing Lin🇨🇳 · Pedro Pasquini🇨🇳 · Jian Tang🇨🇳 · Sampsa Vihonen🇨🇳

    In light of the increasing hints of new physics at the muon $g-2$ and neutrino oscillation experiments, we consider the recently observed tension in the long-baseline neutrino oscillation experiments as a potential indication of Lorentz invariance violation. For this purpose, the latest data from T2K and NO$\nu$A is analysed in presence of non-minimal Lorentz invariance violation. Indeed, we find that isotropic violation in dimensions $D=$ 4, 5 and 6 can alleviate the tension in neutrino oscillation data by 0.4$-$2.4$\sigma$ CL significance, with the isotropic coefficient ${\gamma }_{\tau \tau }^{(5)}=$ 3.58$\times$10${}^{-32}$GeV${}^{-1}$ yielding the best fit. At the same time, the anomalous muon $g-2$ result can be reproduced with an additional non-isotropic violation of $d^{zt}=$ -1.7$\times$10${}^{-25}$. The analysis highlights the possibility of simultaneous relaxation of experimental tensions with Lorentz invariance violation of mixed nature.

    hep-phhep-exPRD(2022)·9 citations
23. 23*

    On the $QQ\bar{q}\bar{q}$-Quark Potential in String Models

    Oleg Andreev🇷🇺

    We propose a string theory construction for the system of two heavy quarks and two light antiquarks. The potential of the system is a function of separation between the quarks. We define a critical separation distance below which the system can be thought of mainly as a compact tetraquark. The results show the universality of the string tension and factorization at small separations expected from heavy quark-diquark symmetry. Our estimate of the screening length is in the range of lattice QCD. We also make a comparison with the potential of the $QQq$ system. The potentials look very similar at small quark separations but at larger separations they differ. The reason for this is that the flattening of the potentials happens at two well-separated scales as follows from the two different mechanisms: string breaking by light quarks for $QQq$ and string junction annihilation for $QQ\bar{q}\bar{q}$. Moreover, a similar construction can also be applied to the $\bar{Q}\bar{Q}qq$ system.

    hep-phhep-lathep-thnucl-thPRD(2022)·27 citations
24. 24*

    Axion-Gauge Field Dynamics with Backreaction

    Koji Ishiwata🇯🇵 · Eiichiro Komatsu🇩🇪 · Ippei Obata🇩🇪

    Phenomenological success of inflation models with axion and SU(2) gauge fields relies crucially on control of backreaction from particle production. Most of the previous study only demanded the backreaction terms in equations of motion for axion and gauge fields be small on the basis of order-of-magnitude estimation. In this paper, we solve the equations of motion with backreaction for a wide range of parameters of the spectator axion-SU(2) model. First, we find a new slow-roll solution of the axion-SU(2) system in the absence of backreaction. Next, we obtain accurate conditions for stable slow-roll solutions in the presence of backreaction. Finally, we show that the amplitude of primordial gravitational waves sourced by the gauge fields can exceed that of quantum vacuum fluctuations in spacetime by a large factor, without backreaction spoiling slow-roll dynamics. Imposing additional constraints on the power spectra of scalar and tensor modes measured at CMB scales, we find that the sourced contribution can be more than ten times the vacuum one. Imposing further a constraint of scalar modes non-linearly sourced by tensor modes, the two contributions can still be comparable.

    hep-phastro-ph.COJCAP(2022)·40 citations
25. 25*

    Chiral Symmetry Restoration, Thermal Resonances and the $U(1{)}_A$ symmetry

    Angel Gómez Nicola🇪🇸 · Jacobo Ruiz de Elvira🇪🇸 · Andrea Vioque-Rodríguez🇪🇸

    We discuss recent results regarding the interplay between chiral and $U(1{)}_A$ symmetry restoration, both from the point of view of Ward Identities relating meson susceptibilities and quark condensates, and from the behaviour of light meson resonances at finite temperature

    hep-phPoS(2022)·0 citations
26. 26*

    The factorization-assisted topological-amplitude approach and its applications

    Qin Qin🇨🇳 · Chao Wang🇨🇳 · Di Wang🇨🇳 · Si-Hong Zhou🇨🇳

    Heavy meson decays provide an important platform for studies of both QCD and electroweak dynamics, which may contain some portals to understanding of nonperturbative QCD and physics beyond the Standard Model. The factorization-assisted topological-amplitude approach was proposed to study two-body non-leptonic $D$ meson decays, where a promising QCD inspired approach from first principles is still missing. It was also applied to $B$ meson decays whose subleading power contributions are difficult to calculate. By factorizing topological amplitudes into short distance Wilson coefficients and long distance hadronic matrix elements either to be calculated or to be parameterized, it provides an effective framework to extract information of nonperturbative dynamics involved. With important flavor SU(3) breaking effects taken into account, the data of the decay branching ratios (and also CP asymmetries in $B$ decays) can be fitted well. The extracted amplitudes were further applied to make predictions for other observables, such as CP asymmetries in $D$ decays, mixing parameters in the $D^0-{\bar{D}}^0$ system, and so on. By this review, we will describe the formulation of the factorization-assisted topological-amplitude approach and summarize its applications in $D$ and $B$ meson decays and highlight some of its achievements.

    hep-phFront.Phys.(Beijing)(2023)·13 citations
27. 27*

    Stochastic inflation from quantum field theory and the parametric dependence of the effective noise amplitude

    Jens O. Andersen🇳🇴 · Magdalena Eriksson🇳🇴 · Anders Tranberg🇳🇴

    The non-linear dynamics of long-wavelength cosmological fluctuations may be phrased in terms of an effective classical, but stochastic evolution equation. The stochastic noise represents short-wavelength modes that continually redshift into the long-wavelength domain. The effective evolution may be derived from first principles quantum field theory in an expanding background, through a sequence of approximations calling for additional scrutiny. We perform such an analysis, putting particular emphasis on the amplitude of the stochastic noise, which ultimately determines the cosmological correlations and provides a non-perturbative IR regulator to the dynamics.

    hep-phJHEP(2022)·18 citations
28. 28*

    Fiducial perturbative power corrections within the q${}_{\mathbf{T}}$ subtraction formalism

    Stefano Camarda🇨🇭 · Leandro Cieri🇪🇸 · Giancarlo Ferrera🇮🇹

    We consider higher-order QCD corrections to the production of high-mass systems in hadron collisions within the transverse-momentum (q${}_{\mathrm{T}}$) subtraction formalism. We present a method to consistently remove the linear power corrections in q${}_{\mathrm{T}}$ which appears when fiducial kinematical cuts are applied on the final state system. We consider explicitly the case of fiducial cross sections for Drell-Yan lepton pair production at the Large Hadron Collider up to next-to-next-to-next-to-leading order (N${}^3$LO) in QCD. We have implemented our method within the DYTurbo numerical program and we have obtained perturbative predictions which are in agreement at the per mille level with those obtained with local subtraction formalisms up to the next-to-next-to-leading order (NNLO). At the N3LO we are able to provide predictions for fiducial cross sections with numerical accuracy at the per mille level.

    hep-phEPJC(2022)·52 citations
29. 29*

    New Developments in KKMChh: Quark-Level Exponentiated Radiative Corrections and Semi-analytical Results

    S. A. Yost (1)🇺🇸 · M. Dittrich (2)🇺🇸 · S. Jadach (3)🇵🇱 · Z. Wąs (3)🇵🇱 · B. F. L. Ward (4) ((1) The Citadel, The Military College of South Carolina, (2) University of Florida, Gainesville, (3) Institute of Nuclear Physics, Polish Academy of Sciences, (4) Baylor University)🇺🇸

    We describe a new semi-analytical program, KKhhFoam, which provides a simplified framework for testing the amplitude-level exponentiation scheme (CEEX) of the full KKMChh program in the semi-soft limit. The structure of the KKhhFoam integrand is also helpful for elucidating the structure of CEEX. We also discuss the representation of ISR in KKMChh and compare the ISR added by KKMChh to the effect of switching to a QED-corrected PDF, at the individual quark level, and suggest a new approach to running KKMChh with QED-corrected PDFs.

    hep-phSciPost Phys.Proc.(2022)·1 citation
30. 30*

    Correlators of heavy-light quark currents in HQET: OPE at three loops

    K. G. Chetyrkin🇩🇪 · A. G. Grozin🇷🇺

    Coefficient functions of the operator product expansion of correlators of HQET heavy--light quark currents are calculated up operators of dimension 4 up to to 3 loops.

    hep-phNPB(2022)·5 citations
31. 31*

    Large Energy Singles at JUNO from Atmospheric Neutrinos and Dark Matter

    Bhavesh Chauhan🇮🇳 · Basudeb Dasgupta🇮🇳 · Amol Dighe🇮🇳

    Large liquid scintillator detectors, such as JUNO, present a new opportunity to study neutral current events from the low-energy end of the atmospheric neutrinos, and possible new physics signals due to light dark matter. We carefully study the possibility of detecting ``Large Energy Singles'' (LES), i.e., events with visible scintillation energy $>15$\,MeV, but no other associated tags. For an effective exposure of 20 kton-yr and considering only Standard Model physics, we expect the LES sample to contain $\sim 40$ events from scattering on free protons and $\sim 108$ events from interaction with carbon, from neutral-current interactions of atmospheric neutrinos. Backgrounds, largely due to $\beta$-decays of cosmogenic isotopes, are shown to be significant only below 15 MeV visible energy. The LES sample at JUNO can competitively probe a variety of new physics scenarios, such as boosted dark matter and annihilation of galactic dark matter to sterile neutrinos.

    hep-phhep-exPRD(2022)·16 citations
32. 32*

    The information content of jet quenching and machine learning assisted observable design

    Yue Shi Lai🇺🇸 · James Mulligan🇺🇸 · Mateusz Płoskoń🇺🇸 · Felix Ringer🇺🇸

    Jets produced in high-energy heavy-ion collisions are modified compared to those in proton-proton collisions due to their interaction with the deconfined, strongly-coupled quark-gluon plasma (QGP). In this work, we employ machine learning techniques to identify important features that distinguish jets produced in heavy-ion collisions from jets produced in proton-proton collisions. We formulate the problem using binary classification and focus on leveraging machine learning in ways that inform theoretical calculations of jet modification: (i) we quantify the information content in terms of Infrared Collinear (IRC)-safety and in terms of hard vs. soft emissions, (ii) we identify optimally discriminating observables that are in principle calculable in perturbative QCD, and (iii) we assess the information loss due to the heavy-ion underlying event and background subtraction algorithms. We illustrate our methodology using Monte Carlo event generators, where we find that important information about jet quenching is contained not only in hard splittings but also in soft emissions and IRC-unsafe physics inside the jet. This information appears to be significantly reduced by the presence of the underlying event. We discuss the implications of this for the prospect of using jet quenching to extract properties of the QGP. Since the training labels are exactly known, this methodology can be used directly on experimental data without reliance on modeling. We outline a proposal for how such an experimental analysis can be carried out, and how it can guide future measurements.

    hep-phhep-exnucl-exnucl-thJHEP(2022)·29 citations
33. 33*

    Mixed QCD-electroweak corrections to $Z$ and $W$ boson production and their impact on the $W$ mass measurements at the LHC

    Arnd Behring🇩🇪

    We report on recently computed mixed QCD-electroweak corrections to on-shell $W$ and $Z$ boson production. We use these differential predictions to estimate their impact on the $W$ boson mass determination at the LHC.

    hep-phSciPost Phys.Proc.(2022)·0 citations
34. 34*

    $\mathbf{B}-\mathbf{L}$ model with ${\mathbf{D}}_4\times {\mathbf{Z}}_4\times {\mathbf{Z}}_2$ symmetry for fermion mass hierarchies and mixings

    V. V. Vien🇻🇳

    We construct a gauge $B-L$ model with $D_4\times Z_4\times Z_2$ symmetry that can explain the quark and lepton mass hierarchies and their mixings with the realistic CP phases via the type-I seesaw mechanism. Six quark mases, three quark mixing angles and CP phase in the quark sector can get the central values and Yukawa couplings in the quark sector are diluted a range of three orders of magnitude difference by the perturbation theory at the first order. For neutrino sector, the smallness of neutrino mass is achieved by the Type-I seesaw mechanism. Both inverted and normal neutrino mass hierarchies are in consistent with the experimental data. The prediction for the sum of neutrino masses for normal and inverted hierarchies, the effective neutrino masses and the Dirac CP phase are well consistent with all the recent limits.

    hep-phCPC(2024)·3 citations
35. 35*

    Leptogenesis and eV scale sterile neutrino

    Srubabati Goswami🇮🇳 · Vishnudath K. N.🇮🇳 · Ananya Mukherjee🇮🇳 · Nimmala Narendra🇮🇳

    We consider the minimal extended seesaw model which can accommodate an eV scale sterile neutrino. The scenario also includes three heavy right handed neutrinos in addition to the light sterile neutrino. In this model, the active-sterile mixing act as non-unitary parameters. If the values of these mixing angles are of $\mathcal{O}(0.1)$, the model introduces deviation of the PMNS matrix from unitarity to this order. We find that the oscillation data from various experiments imposes an upper bound on the lightest heavy neutrino mass scale as $\sim 10^{11}$ GeV in the context of this model. We study {\it vanilla} leptogenesis in this scheme, where the decay of the heavy right handed neutrinos in the early universe can give rise to the observed baryon asymmetry. Here, even though the eV scale sterile neutrino does not participate directly in leptogenesis, its effect is manifested through the non-unitary effects. We find that the parameter space that can give rise to successful leptogenesis is constrained by the bounds on the active-sterile mixing as obtained from the global analysis.

    hep-phPRD(2022)·6 citations
36. 36*

    One-loop corrections to ALP couplings

    J. Bonilla🇪🇸 · I. Brivio🇩🇪 · M.B. Gavela🇪🇸 · V. Sanz🇪🇸

    We derive the one-loop contributions to ALP-SM effective couplings, including all finite corrections. The complete leading-order -- dimension five -- effective linear Lagrangian is considered. The ALP is left off-shell, which is of particular impact on LHC and accelerator searches of ALP couplings to $\gamma \gamma$, $ZZ$, $Z\gamma$, $WW$, gluons and fermions. All results are obtained in the covariant $R_{\xi }$ gauge. A few phenomenological consequences are also explored as illustration, with flavour diagonal channels in the case of fermions: in particular, we explore constraints on the coupling of the ALP to top quarks, that can be extracted from LHC data, from astrophysical sources and from Dark Matter direct detection experiments such as PandaX, LUX and XENON1T.

    hep-phPoS(2022)·1 citation
37. 37*

    Reconstructing spectral functions via automatic differentiation

    Lingxiao Wang🇩🇪 · Shuzhe Shi🇨🇦 · Kai Zhou🇩🇪

    Reconstructing spectral functions from Euclidean Green's functions is an important inverse problem in many-body physics. However, the inversion is proved to be ill-posed in the realistic systems with noisy Green's functions. In this Letter, we propose an automatic differentiation(AD) framework as a generic tool for the spectral reconstruction from propagator observable. Exploiting the neural networks' regularization as a non-local smoothness regulator of the spectral function, we represent spectral functions by neural networks and use the propagator's reconstruction error to optimize the network parameters unsupervisedly. In the training process, except for the positive-definite form for the spectral function, there are no other explicit physical priors embedded into the neural networks. The reconstruction performance is assessed through relative entropy and mean square error for two different network representations. Compared to the maximum entropy method, the AD framework achieves better performance in the large-noise situation. It is noted that the freedom of introducing non-local regularization is an inherent advantage of the present framework and may lead to substantial improvements in solving inverse problems.

    hep-phcs.LGhep-latPRD(2022)·45 citations
38. 38*

    Dynamically groomed jet radius in heavy-ion collisions

    Paul Caucal🇺🇸 · Alba Soto-Ontoso🇫🇷 · Adam Takacs🇳🇴

    We explore the ability of a recently proposed jet substructure technique, Dynamical Grooming, to pin down the properties of the Quark-Gluon Plasma formed in ultra-relativistic heavy-ion collisions. In particular, we compute, both analytically and via Monte-Carlo simulations, the opening angle ${\theta }_g$ of the hardest splitting in the jet as defined by Dynamical Grooming. Our calculation, grounded in perturbative QCD, accounts for the factorization in time between vacuum-like and medium-induced processes in the double logarithmic approximation. We observe that the dominating scale in the ${\theta }_g$-distribution is the decoherence angle ${\theta }_c$ which characterises the resolution power of the medium to propagating color probes. This feature also persists in strong coupling models for jet quenching. We further propose for potential experimental measurements a suitable combination of the Dynamical Grooming condition and the jet radius that leads to a pQCD dominated observable with a very small sensitivity ($\le 10\%$) to medium response.

    hep-phnucl-thPRD(2022)·61 citations
39. 39*

    Comparing Machine Learning and Interpolation Methods for Loop-Level Calculations

    Ibrahim Chahrour🇺🇸 · James D. Wells🇺🇸

    The need to approximate functions is ubiquitous in science, either due to empirical constraints or high computational cost of accessing the function. In high-energy physics, the precise computation of the scattering cross-section of a process requires the evaluation of computationally intensive integrals. A wide variety of methods in machine learning have been used to tackle this problem, but often the motivation of using one method over another is lacking. Comparing these methods is typically highly dependent on the problem at hand, so we specify to the case where we can evaluate the function a large number of times, after which quick and accurate evaluation can take place. We consider four interpolation and three machine learning techniques and compare their performance on three toy functions, the four-point scalar Passarino-Veltman $D_0$ function, and the two-loop self-energy master integral $M$. We find that in low dimensions ($d=3$), traditional interpolation techniques like the Radial Basis Function perform very well, but in higher dimensions ($d=5,6,9$) we find that multi-layer perceptrons (a.k.a neural networks) do not suffer as much from the curse of dimensionality and provide the fastest and most accurate predictions.

    hep-phcs.LGSciPost Phys.(2022)·13 citations
40. 40*

    Dark Matter abundance via thermal decays and leptoquark mediators

    Benedetta Belfatto🇮🇹 · Dario Buttazzo🇮🇹 · Christian Gross🇮🇹 · Paolo Panci🇮🇹 · Alessandro Strumia🇮🇹 · Natascia Vignaroli🇮🇹 · Ludovico Vittorio🇮🇹 · Ryoutaro Watanabe🇮🇹

    We explore a new mechanism for reproducing the Dark Matter (DM) abundance: scatterings of one DM particle on light Standard Model particles. Strong bounds on its decays can be satisfied if DM undergoes freeze-in and has a mass around or below the pion mass. This happens, for example, in theories with a right-handed neutrino interacting with charged fermions through a leptoquark exchange. These leptoquarks can be linked to the ones motivated by the B-physics anomalies if assumptions about the flavour structure are made. DM signals are unusual, with interesting possibilities for direct and indirect detection. Achieving thermal freeze-out instead requires models with more than one DM flavour, and couplings parametrically smaller than what needed by the usual pair annihilations.

    hep-phastro-ph.COJHEP(2022)·19 citations
41. 41*

    Thermal Dark Matter from Freezeout of Inverse Decays

    Ronny Frumkin🇮🇱 · Yonit Hochberg🇮🇱 · Eric Kuflik🇮🇱 · Hitoshi Murayama🇯🇵

    We propose a new thermal dark matter candidate whose abundance is determined by the freezeout of inverse decays. The relic abundance depends parametrically only on a decay width, while matching the observed value requires that the coupling determining the width-and the width itself-should be exponentially small. The dark matter is therefore very weakly coupled to the Standard Model, evading conventional searches. This INverse DecaY ('INDY') dark matter can be discovered by searching for the long-lived particle that decays into the dark matter at future planned experiments.

    hep-phPRL(2023)·25 citations
42. 42*

    Cosmic Neutrino Background Detection in Large-Neutrino-Mass Cosmologies

    James Alvey🇳🇱 · Miguel Escudero🇩🇪 · Nashwan Sabti🇬🇧 · Thomas Schwetz🇩🇪

    The Cosmic Neutrino Background (CNB) is a definite prediction of the standard cosmological model and its direct discovery would represent a milestone in cosmology and neutrino physics. In this work, we consider the capture of relic neutrinos on a tritium target as a possible way to detect the CNB, as aimed for by the PTOLEMY project. Crucial parameters for this measurement are the absolute neutrino mass $m_{\nu }$ and the local neutrino number density $n_{\nu }^{\mathrm{loc}}$. Within the $\Lambda$CDM model, cosmology provides a stringent upper limit on the sum of neutrino masses of $\sum m_{\nu }<0.12\mathrm{eV}$, with further improvements expected soon from galaxy surveys by DESI and EUCLID. This makes the prospects for a CNB detection and a neutrino mass measurement in the laboratory very difficult. In this context, we consider a set of non-standard cosmological models that allow for large neutrino masses ($m_{\nu }\sim 1\mathrm{eV}$), potentially in reach of the KATRIN neutrino mass experiment or upcoming neutrinoless double-beta decay searches. We show that the CNB detection prospects could be much higher in some of these models compared to those in $\Lambda$CDM, and discuss the potential for such a detection to discriminate between cosmological scenarios. Moreover, we provide a simple rule to estimate the required values of energy resolution, exposure, and background rate for a PTOLEMY-like experiment to cover a certain region in the $(m_{\nu },n_{\nu }^{\mathrm{loc}})$ parameter space. Alongside this paper, we publicly release a code to calculate the CNB sensitivity in a given cosmological model.

    hep-phastro-ph.COhep-exPRD(2022)·57 citations
43. 43*

    Freezing-in a hot bath: resonances, medium effects and phase transitions

    Torsten Bringmann🇳🇴 · Saniya Heeba🇨🇦 · Felix Kahlhoefer🇩🇪 · Kristian Vangsnes🇳🇴

    Relic density calculations of dark matter freezing out from the primordial plasma have reached a high level of sophistication, with several numerical tools readily available that match the observationally required accuracy. Dark matter production via the freeze-in mechanism, on the other hand, is sensitive to much higher temperatures than in the freeze-out case, implying both technical and computational difficulties when aiming for the same level of precision. We revisit the formulation of freeze-in production in a way that facilitates the inclusion of in-medium corrections like plasma effects and the spin statistics of relativistic quantum gases, as well as the temperature dependence of dark matter production rates induced by the electroweak and strong phase transitions, and we discuss in detail the additional complications arising in the presence of $s$-channel resonances. We illustrate our approach in the context of Higgs portal models, and provide the most accurate calculation to date of the freeze-in abundance of Scalar Singlet dark matter. We explore in particular the case of small reheating temperatures, for which the couplings implied by the freeze-in mechanism may be testable at the LHC. Together with this article we present a major update 6.3 of DarkSUSY with the added capability of performing general freeze-in calculations, including all complications mentioned above.

    hep-phastro-ph.COJHEP(2022)·51 citations
44. 44*

    Using DUNE to Shed Light on the Electromagnetic Properties of Neutrinos

    Varun Mathur🇺🇸 · Ian M. Shoemaker🇺🇸 · Zahra Tabrizi🇺🇸

    We study future DUNE sensitivity to various electromagnetic couplings of neutrinos, including magnetic moments, milli-charges, and charge radii. The DUNE PRISM capabilities play a crucial role in constraining the electron flavored couplings. We find that DUNE will be able to place the strongest terrestrial constraint on the muon-neutrino magnetic moment by improving on LSND's bounds by roughly a factor of two, although Borexino's solar constraint will still be stronger. For the muon neutrino milli-charge DUNE can place the leading experimental bound, with two orders of magnitude improvement compared to the existing COHERENT constraint. Finally, DUNE may be able to test the SM prediction for the muon neutrino charge radius, by placing a constraint two times better than CHARM-II and CCFR experiments.

    hep-phJHEP(2022)·28 citations
45. 45*

    The Scalar Potential of Supersymmetric $SU(3{)}_C\times SU(3{)}_L\times U(1{)}_N$ Model

    M. C. Rodriguez🇧🇷

    We will study in details the full scalar potential of the Minimal Supersymmetric $SU(3{)}_C\times SU(3{)}_L\times U(1{)}_N$ Model. We will present numerical predictions for all the usual scalars of this model, we will show that the mass of the light scalar of CP par is $125.5$ GeV, such that its masses satisfy the current experimental constraints.

    hep-ph1 citation
46. 46*

    The use of CEvNS to monitor spent nuclear fuel

    Caroline von Raesfeld🇺🇸 · Patrick Huber🇺🇸

    Increasing amounts of spent nuclear fuel are stored in dry storage casks for prolonged periods of time. To date no effective technology exists to re-verify cask contents should this become necessary. We explore the applicability of Coherent-Elastic Neutrino-Nucleus Scattering (CEvNS) to monitor the content of spent nuclear fuel (SNF) from dry storage casks. SNF produces neutrinos chiefly from ${}^{90}$Sr decays. We compare these results with what can be achieved via Inverse Beta Decay (IBD). We demonstrate that at low nuclear recoil energies CEvNS events rates exceed the IBD event rates by 2--3 orders of magnitude for a given detector mass. We find that a 10\,kg argon or germanium detector 3 meters from a fuel cask can detect over 100 events per year if a nuclear recoil threshold under 100 eV can be achieved.

    hep-phPRD(2022)·19 citations
47. 47*

    Hidden charm mesons in nuclear matter and nuclei

    J.J. Cobos-Martínez🇲🇽 · K. Tsushima🇧🇷 · G. Krein🇧🇷 · A.W. Thomas🇦🇺

    Recent results for the ${\eta }_c$- and $J/\psi$-nucleus bound state energies for various nuclei are presented. The attractive potentials for the ${\eta }_c$ and $J/\psi$ mesons in the nuclear medium originate, respectively, from the in-medium enhanced $D{D}^{\ast }$ and $D\bar{D}$ loops in the ${\eta }_c$ and $J/\psi$ self energies. Our results suggest that the ${\eta }_c$ and $J/\psi$ mesons should form bound states with all the nuclei considered.

    ↳ nucl-thhep-exhep-phnucl-exPoS(2022)·2 citations
48. 48*

    Observation of $J/\psi$ decays to $e^{+}{e}^{-}{e}^{+}{e}^{-}$ and $e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$

    BESIII Collaboration: M. Ablikim · M. N. Achasov · P. Adlarson · M. Albrecht · R. Aliberti · A. Amoroso · M. R. An · Q. An · X. H. Bai · Y. Bai · O. Bakina · R. Baldini Ferroli and 542 other authors

    Using a data sample of $4.481\times 10^8{\psi }^{\prime }$ events collected with the BESIII detector, we report the first observation of the four-lepton-decays $J/\psi \to e^{+}{e}^{-}{e}^{+}{e}^{-}$ and $J/\psi \to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$ utilizing the process ${\psi }^{\prime }\to {\pi }^{+}{\pi }^{-}J/\psi$. The branching fractions are determined to be $[5.48\pm 0.31(\mathrm{stat})\pm 0.45(\mathrm{syst})]\times 10^{-5}$ and $[3.53\pm 0.22(\mathrm{stat})\pm 0.13(\mathrm{syst})]\times 10^{-5}$, respectively. The results are consistent with theoretical predictions. No significant signal is observed for $J/\psi \to {\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$, and an upper limit on the branching fraction is set at $1.6\times 10^{-6}$ at the 90$\%$ confidence level. A CP asymmetry observable is constructed for the first two channels, which is measured to be $(-0.012\pm 0.054\pm 0.010)$ and $(0.062\pm 0.059\pm 0.006)$, respectively. No evidence for CP violation is observed in this process.

    ↳ hep-exhep-phPRD(2024)·9 citations
49. 49*

    About the Coleman Instantons in D Dimensions

    Viatcheslav Mukhanov🇩🇪 · Alexander Sorin🇷🇺

    We identify an infinite class of unbounded potentials for which the Coleman instantons do not exist in D-dimensional spacetime. For such potentials, the decay of a false vacuum is described by the new instantons introduced in [5,6,4]. For each spacetime dimension D, we also construct the two different classes of potentials for which the instanton equations are exactly solvable.

    ↳ hep-thgr-qchep-phmath-ph+2PLB(2022)·4 citations
50. 50*

    Coupled baryon, electric charge and strangeness fluctuations in heavy-ion collisions

    Grégoire Pihan🇫🇷 · Marcus Bluhm🇫🇷 · Marlene Nahrgang🇫🇷

    We present for the first time quantitative results for the coupled dynamics of second order fluctuations in the three conserved charges of QCD based on stochastic diffusion equations for a Bjorken-type expanding hadronic medium.

    ↳ nucl-thhep-phEPJ Web Conf.(2022)·1 citation
51. 51*

    Momentum dependence of near-threshold photoproduction of ${\Xi }^{-}$ hyperons off nuclei and their properties in the nuclear medium

    E. Ya. Paryev🇷🇺

    We study the near-threshold inclusive photoproduction of ${\Xi }^{-}$ hyperons off ${}^{12}$C and ${}^{184}$W target nuclei within a first-collision model relying on the nuclear spectral function and including incoherent ${\Xi }^{-}$ production in direct elementary $\gamma p\to K^{+}{K}^{+}{\Xi }^{-}$ and $\gamma n\to K^{+}{K}^0{\Xi }^{-}$ processes. The model takes into account the impact of the nuclear effective scalar $K^{+}$, $K^0$, ${\Xi }^{-}$ and their Coulomb potentials on these processes as well as the absorption of final ${\Xi }^{-}$ hyperons in nuclear matter, the binding of intranuclear nucleons and their Fermi motion. We calculate the absolute differential cross sections and their ratios for the production of ${\Xi }^{-}$ hyperons off these nuclei at laboratory polar angles $\le$ 45${}^{\circ }$ by photons with energies of 2.5 and 3.0 GeV, with and without imposing the phase space constraints on the ${\Xi }^{-}$ emission angle in the respective $\gamma p$ center-of-mass system. We also calculate the momentum dependence of the transparency ratio for ${\Xi }^{-}$ hyperons for the ${}^{184}$W/${}^{12}$C combination at these photon energies. We show that the ${\Xi }^{-}$ momentum distributions (absolute and relative) at the adopted initial photon energies possess, contrary to the transparency ratio for ${\Xi }^{-}$ hyperons, a definite sensitivity to the considered changes in the scalar ${\Xi }^{-}$ nuclear mean-field potential at saturation density ${\rho }_0$ in the low-momentum range of 0.1--0.8 GeV/c. Therefore, the precise measurements of these distributions in a dedicated experiment at the CEBAF facility will provide valuable information on the ${\Xi }^{-}$ in-medium properties, which will be supplementary to that inferred from studying of the ($K^{-}$,$K^{+}$) reactions at initial momenta of 1.6--1.8 GeV/c.

    ↳ nucl-thhep-phnucl-exNPA(2022)·2 citations
52. 52*

    Understanding BBN: the physics and its history

    Michael S. Turner🇺🇸 · KICP/UChicago · The Kavli Foundation

    Big-bang nucleosynthesis (BBN), today a pillar of modern cosmology, began with the trailblazing 1948 paper of Alpher, Bethe and Gamow. In it, they proposed non-equilibrium nuclear processes in the early Universe ($t\sim 1000$sec) and an early radiation-dominated phase to explain the abundances of all the chemical elements. Their model was fundamentally flawed, but initiated a complex and interesting path to the modern theory of BBN, which explains only the abundances of the lightest chemical elements (mostly ${}^4$He) and the discovery of the cosmic microwave background (CMB). The purpose of this paper is to clarify the basic physics of BBN, adding some new insights, and to describe how the modern theory developed. I finish with a discussion of two misunderstandings about BBN that still persist and the tale of the pre-discovery predictions of the temperature of the CMB and the missed opportunity it turned out to be.

    ↳ astro-ph.COhep-ph7 citations
53. 53*

    Comment on ''Quantum sensor networks as exotic field telescopes for multi-messenger astronomy''

    Yevgeny V. Stadnik🇯🇵

    In the recent work [Dailey et al., Nature Astronomy 5, 150 (2021)], it was claimed that networks of quantum sensors can be used as sensitive multi-messenger probes of astrophysical phenomena that produce intense bursts of relativistic bosonic waves which interact non-gravitationally with ordinary matter. The most promising possibility considered in [Ibid.] involved clock-based searches for quadratic scalar-type interactions, with greatly diminished reach in the case of magnetometer-based searches for derivative-pseudoscalar-type interactions and clock-based searches for linear scalar-type interactions. In this note, we point out that the aforementioned work overlooked the ''back action'' of ordinary matter on scalar waves with quadratic interactions and that accounting for back-action effects can drastically affect the detection prospects of clock networks. In particular, back action can cause strong screening of scalar waves near Earth's surface and by the apparatus itself, rendering clock experiments insensitive to extraterrestrial sources of relativistic scalar waves. Additionally, back-action effects can retard the propagation of scalar waves through the interstellar and intergalactic media, significantly delaying the arrival of scalar waves at Earth compared to their gravitational-wave counterparts and thereby preventing multi-messenger astronomy on human timescales.

    ↳ gr-qcastro-ph.IMhep-phphysics.atom-ph+1Nature Astron.(2024)·10 citations
54. 54*

    Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review

    Shanzhen Chen🇨🇳 · Yiming Li🇨🇳 · Wenbin Qian🇨🇳 · Zhihong Shen🇨🇳 · Yuehong Xie🇨🇳 · Zhenwei Yang🇯🇵 · Liming Zhang🇨🇳 · Yanxi Zhang🇨🇳

    Heavy flavour physics provides excellent opportunities to indirectly search for new physics at very high energy scales and to study hadron properties for deep understanding of the strong interaction. The LHCb experiment has been playing a leading role in the study of heavy flavour physics since the start of the LHC operations about ten years ago, and made a range of high-precision measurements and unexpected discoveries, which may have far-reaching implications on the field of particle physics. This review highlights a selection of the most influential physics results on CP violation, rare decays, and heavy flavour production and spectroscopy obtained by LHCb using the data collected during the first two operation periods of the LHC. The upgrade plan of LHCb and the physics prospects are also briefly discussed.

    ↳ hep-exhep-phFront.Phys.(2023)·49 citations
55. 55*

    The gradient flow at higher orders in perturbation theory

    Robert Harlander🇩🇪

    Various results for higher-order perturbative calculations in the gradient-flow formalism are reviewed, including the gradient-flow beta function and the small-flow-time expansion of the hadronic vacuum polarization and the energy-momentum tensor. In addition, the strategy of regions is outlined in order to obtain systematic expansions of gradient-flow integrals, for example at large and small flow times.

    ↳ hep-lathep-phPoS(2022)·7 citations
56. 56*

    Non-Perturbative Bounds for Semileptonic Decays in Lattice QCD

    Matteo Di Carlo🇬🇧 · Guido Martinelli🇮🇹 · Manuel Naviglio🇮🇹 · Francesco Sanfilippo🇮🇹 · Silvano Simula🇮🇹 · Ludovico Vittorio🇮🇹

    We present a new method aiming at a non-perturbative, model-independent determination of the momentum dependence of the form factors entering semileptonic decays using unitarity and analyticity constraints. We extend the original proposal and, using suitable two-point functions computed non-perturbatively, we determine the form factors at low-momentum transfer $q^2$ from those computed explicitly on the lattice at large $q^2$, without making any assumption about their $q^2$ dependence. As a training ground we apply the new method to the analysis of the lattice data of the semileptonic $D\to K\ell {\nu }_{\ell }$ decays obtained both at finite values of the lattice spacing and at the physical pion point in the continuum limit. We show that, starting from a limited set of data at large $q^2$, it is possible to determine quite precisely the form factors in a model independent way in the full kinematical range, obtaining a remarkable agreement with the direct calculation of the form factors. This finding opens the possibility to obtain non-perturbatively the form factors entering the semileptonic B decays in the full kinematical range.

    ↳ hep-lathep-exhep-phPoS(2022)·0 citations
57. 57*

    Competition between diffusion and rapid expansion and its impact on critical fluctuations in heavy-ion collisions

    Grégoire Pihan · Marcus Bluhm · Masakiyo Kitazawa · Marlene Nahrgang

    We study the impact of the competition between the expansion of the medium created in heavy-ion collisions and its diffusive properties on the critical fluctuations of the net-baryon density. As the relaxation time of the fluctuations is connected with the diffusive properties, the latter determine the in- or out-of-equilibrium nature of the net-baryon density fluctuations during the fireball evolution. This may result in important consequences for the phenomenological interpretation of heavy-ion collision data. We study three possible situations that can occur as a result of the competition between diffusion and expansion and discuss the impact of this competition on the integrated second and fourth order cumulants of net-baryon density fluctuations at freeze-out in these situations.

    ↳ nucl-thhep-phPoS(2022)·0 citations
58. 58*

    Search for Low-Energy Signals from Fast Radio Bursts with the Borexino Detector

    (Borexino Collaboration) S. Appel🇩🇪 · Z. Bagdasarian🇺🇸 · D. Basilico🇮🇹 · G. Bellini🇮🇹 · J. Benziger🇺🇸 · R. Biondi🇮🇹 · B. Caccianiga🇮🇹 · F. Calaprice🇺🇸 · A. Caminata🇮🇹 · A. Chepurnov🇷🇺 · D. D'Angelo🇮🇹 · A. Derbin🇷🇺 and 68 other authors

    The search for neutrino events in correlation with several of the most intense fast radio bursts (FRBs) has been performed using the Borexino data. We have searched for signals with visible energies above $250$~keV within a time window of $\pm$1000~s corresponding to the detection time of a particular FRB. We also applied an alternative approach based on searching for specific shapes of neutrino-electron scattering spectra in the full exposure spectrum of the Borexino detector. In particular, two incoming neutrino spectra were considered: the monoenergetic line and the spectrum expected from supernovae. The same spectra were considered for electron antineutrinos detected through the inverse beta-decay reaction. No statistically significant excess over the background was observed. As a result, the strongest upper limits on FRB-associated neutrino fluences of all flavors have been obtained in the $0.5-50$~MeV neutrino energy range.

    ↳ hep-exastro-ph.IMhep-phEPJC(2022)·3 citations
59. 59*

    Progress in $Sp(2N)$ lattice gauge theories

    Ed Bennett🇬🇧 · Jack Holligan🇬🇧 · Deog Ki Hong🇰🇷 · Ho Hsiao🇹🇼 · Jong-Wan Lee🇰🇷 · C.-J. David Lin🇹🇼 · Biagio Lucini🇬🇧 · Michele Mesiti🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇮🇪

    Lattice studies of gauge theories with symplectic gauge groups provide valuable information about gauge dynamics, and complement the results of lattice investigations focused on unitary gauge groups. These theories play a central role in phenomenological contexts such as composite Higgs and strongly interacting dark matter models. We report on recent progress of our lattice research programme, starting from the glueball mass spectrum and the topology of the pure gauge theory. We present our results on the mass spectrum of mesons in the quenched approximation, by varying the number of colours in the symplectic group. For the $Sp(4)$ theory, we focus on results obtained with dynamical fermion matter content comprising both fundamental and 2-index antisymmetric representations of the gauge group, as dictated by a well known model of composite Higgs with partial top compositeness.

    ↳ hep-lathep-phhep-thPoS(2022)·21 citations
60. 60*

    Progress in the determination of Mellin moments of the pion LCDA using the HOPE method

    William Detmold🇺🇸 · Anthony V. Grebe🇺🇸 · Issaku Kanamori🇯🇵 · C.-J. David Lin🇹🇼 · Santanu Mondal🇺🇸 · Robert J. Perry🇹🇼 · Yong Zhao🇺🇸

    The pion light-cone distribution amplitude (LCDA) is a central non-perturbative object of interest for the calculation of high-energy exclusive processes in quantum chromodynamics. In this article, we discuss the calculation of the second and fourth Mellin moment of the pion LCDA using a heavy-quark operator product expansion. The resulting value for the second Mellin moment is $⟨{\xi }^2⟩(\mu =2\text{GeV})=0.210\pm 0.013\text{ (stat.)}\pm 0.034\text{ (sys.)}$. This result is compatible with those from previous determinations of this quantity.

    ↳ hep-lathep-phnucl-thPoS(2022)·4 citations
61. 61*

    Perturbative predictions for color superconductivity on the lattice

    Takeru Yokota🇯🇵 · Yuhma Asano🇯🇵 · Yuta Ito🇯🇵 · Hideo Matsufuru🇯🇵 · Yusuke Namekawa🇯🇵 · Jun Nishimura🇯🇵 · Asato Tsuchiya🇯🇵 · Shoichiro Tsutsui🇯🇵

    We develop a new method to investigate color superconductivity (CSC) on the lattice based on the Thouless criterion, which amounts to solving the linearized gap equation without imposing any ansatz on the structure of the Cooper pairs. We perform explicit calculations at the one-loop level with the staggered fermions on a $8^3\times 128$ lattice and the Wilson fermions on a $4^3\times 128$ lattice, which enables us to obtain the critical $\beta (=6/g^2)$ as a function of the quark chemical potential $\mu$, below which the CSC phase is expected to appear. The obtained critical $\beta$ has sharp peaks at the values of $\mu$ corresponding to the discretized energy levels of quarks similarly to what was observed in previous studies on simplified effective models. From the solution to the linearized gap equation, one can read off the flavor and spatial structures of the Cooper pairs at the critical $\beta$. In the case of massless staggered fermion, in particular, we find that the chiral $\mathrm{U}(1)$ symmetry of the staggered fermions is spontaneously broken by the condensation of the Cooper pairs.

    ↳ hep-lathep-phPoS(2022)·3 citations
62. 62*

    Estimates for the lightest baryon masses in $\mathcal{N}=1$ supersymmetric Yang-Mills theory

    Sajid Ali🇩🇪 · Georg Bergner🇩🇪 · Camilo Lopez🇩🇪 · Istvan Montvay🇩🇪 · Gernot Münster🇩🇪 · Stefano Piemonte🇩🇪

    $\mathcal{N}=1$ supersymmetric Yang-Mills theory describes gluons interacting with gluinos, which are spin-$\frac{1}{2}$ Majorana particles in the adjoint representation of the gauge group. In addition to glueballs and mesonic bound states, the theory contains color neutral bound states of three gluinos, which are analogous to baryons in QCD. We calculate their correlation functions, involving ``sunset diagrams'' and ``spectacle diagrams'', numerically for gauge group SU(2) and present an update on the estimates for the lowest masses.

    ↳ hep-lathep-phPoS(2021)·2 citations
63. 63*

    Quantum fluctuations, particles and entanglement: a discussion towards the solution of the quantum measurement problems

    Kenichi Konishi🇮🇹

    The quantum measurement problems are revisited from a new perspective. One of the main ideas of this work is that the basic entities of our world are various types of particles, elementary or composite. It follows that each elementary process, hence each measurement process at its core, is a spacetime, pointlike, event. Another key idea is that, when a microsystem $\psi$ gets into contact with the experimental device, factorization of $\psi$ rapidly fails and entangled mixed states appear. The wave functions for the microsystem-apparatus coupled systems for different measurement outcomes then lack overlapping spacetime support. It means that the aftermath of each measurement is a single term in the sum: a "wave-function collapse". Our discussion leading to a diagonal density matrix, $\rho =\mathrm{diag}(|c_1{|}^2,\dots ,|c_n{|}^2,\dots )$ shows how the information encoded in the wave function $|\psi ⟩={\sum }_n{c}_n|n⟩$ gets transcribed, via entanglement with the experimental device and environment, into the relative frequencies ${\mathcal{P}}_n=|c_n{|}^2$ for various experimental results $F=f_n$. These results represent new, significant steps towards filling in the logical gaps in the standard interpretation based on Born's rule, and replacing it with a more natural one. Accepting objective reality of quantum fluctuations, independent of any experiments, and independently of human presence, one renounces the idea that in a fundamental, complete theory of Nature the result of each single experiment must necessarily be predictable. A few well-known puzzles such as the Schrödinger cat conundrum and the EPR paradox are briefly reviewed: they can all be naturally explained away.

    ↳ quant-phgr-qchep-phhep-thInt.J.Mod.Phys.A(2022)·10 citations
64. 64*

    Suppression of Fast Neutrino Flavor Conversions Occurring at Large Distances in Core-Collapse Supernovae

    Sajad Abbar🇩🇪 · Francesco Capozzi🇺🇸

    Neutrinos propagating in dense neutrino media such as core-collapse supernovae and neutron star merger remnants can experience the so-called fast flavor conversions on scales much shorter than those expected in vacuum. A very generic class of fast flavor instabilities is the ones which are produced by the backward scattering of neutrinos off the nuclei at relatively large distances from the supernova core. In this study we demonstrate that despite their ubiquity, such fast instabilities are unlikely to cause significant flavor conversions if the population of neutrinos in the backward direction is not large enough. Indeed, the scattering-induced instabilities can mostly impact the neutrinos traveling in the backward direction, which represent only a small fraction of neutrinos at large radii. We show that this can be explained by the shape of the unstable flavor eigenstates, which can be extremely peaked at the backward angles.

    ↳ astro-ph.HEhep-phJCAP(2022)·43 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.