Tue·Mar 23, 2021Tuesday·March 23, 2021

1. 01*

   Non-resonant and offshell effects in top-pair observables

   Silvia Ferrario Ravasio🇬🇧 · Tomáš Ježo🇩🇪

   In these proceedings we investigate the impact of offshell and non-resonant contributions to kinematic distributions in $t\bar{t}$ final states by comparing several next-to-leading-order~(NLO) + parton shower (PS) generators which differ in the way they model these effects. We focus on distributions traditionally used for measurements of fundamental top-quark properties such as its Yukawa coupling or its mass. Given the current experimental uncertainties, we find that such effects can have relatively large impact on the shape of these distributions and are thus mandatory for accurate measurements.

   hep-phhep-ex1 citation
2. 02*

   Standard GRB Spectral Models "Misused"?

   Liang Li🇮🇹

   The standard model characterizing the gamma-ray burst (GRB) spectrum invokes a four-parameter empirical function, the so-called the BAND model. An alternative model named cutoff power law (COMP) implements a power law with an exponential cutoff. These functions achieve almost equally good fits on observed spectra, and are adopted in nearly all of the GRB literature. Here, we reanalyze the sample defined in Li.et al.,2021,ApJS,254,35 (39 bursts including 944 spectra). We classify the spectra by two methods: (1) checking their corner-corner plots of the posteriors to determine well-constrained $\beta$ (BAND-better) and unconstrained $\beta$ (COMP-better) categories; and (2) defining the four groups by difference of the deviance information criterion (DIC). We find inconsistent peaks of the parameter distributions between the BAND-better spectra ($\alpha =-0.64\pm 0.28$ and $\mathrm{lo}{\mathrm{g}}_{10}({\mathrm{E}}_{\mathrm{p}})=\mathrm{lo}{\mathrm{g}}_{10}(191)\pm 0.41$) and the COMP-better spectra ($\alpha =-0.96\pm 0.33$ and $\mathrm{lo}{\mathrm{g}}_{10}({\mathrm{E}}_{\mathrm{p}})=\mathrm{lo}{\mathrm{g}}_{10}(249)\pm 0.40$). With the statistically preferred model and vice versa the misused model defined based on DIC statistics, we also find that the fitted parameters obtained by the misused model (COMP) significantly deviate from those obtained by the statistically preferred model (BAND). This means that if a spectrum is statistically preferred, described as the BAND, applying COMP to derive the spectral parameters will prominently deviate from their intrinsic shape, therefore affecting the physical interpretation. Our analysis indicates that the better or statistically preferred model should be duly examined during GRB spectral analysis. In addition, the $\beta$ distribution exhibits a bimodal structure containing the BAND-better and COMP-better spectra, respectively, implying that BAND and COMP both may have physical origin.

   hep-phApJ(2022)·7 citations
3. 03*

   Relaxation and correlation times of nonequilibrium multiparticle systems

   Maciej Rybczynski🇵🇱 · Grzegorz Wilk🇵🇱 · Zbigniew Wlodarczyk🇵🇱

   Relaxation and correlation times are two parameters used frequently in approximate descriptions of the time development of hadronizing system from some initial state towards distributions observed experimentally. Chosen to reproduce the experimental results they represent, in a sense, the history of the hadronization process. The analysis of their changes with energy is the subject of our work.

   hep-phPRD(2021)·5 citations
4. 04*

   Non-standard neutrino oscillations: perspective from unitarity triangles

   Mehedi Masud🇰🇷 · Poonam Mehta🇮🇳 · Christoph A. Ternes🇮🇹 · Mariam Tortola🇪🇸

   We formulate an alternative approach based on unitarity triangles to describe neutrino oscillations in presence of non-standard interactions (NSI). Using perturbation theory, we derive the expression for the oscillation probability in case of NSI and cast it in terms of the three independent parameters of the leptonic unitarity triangle (LUT). The form invariance of the probability expression (even in presence of new physics scenario as long as the mixing matrix is unitary) facilitates a neat geometric view of neutrino oscillations in terms of LUT. We examine the regime of validity of perturbative expansions in the NSI case and make comparisons with approximate expressions existing in literature. We uncover some interesting dependencies on NSI terms while studying the evolution of LUT parameters and the Jarlskog invariant. Interestingly, the geometric approach based on LUT allows us to express the oscillation probabilities for a given pair of neutrino flavours in terms of only three (and not four) degrees of freedom which are related to the geometric properties (sides and angles) of the triangle. Moreover, the LUT parameters are invariant under rephasing transformations and independent of the parameterization adopted.

   hep-phJHEP(2021)·12 citations
5. 05*

   A unified statistical approach to explain the transverse momentum spectra in hadron-hadron collision

   Rohit Gupta🇮🇳 · Shubhangi Jain🇮🇳 · Satyajit Jena🇮🇳

   Thermodynamical description of the system created during high energy collision requires a proper thermodynamical framework to study the distribution of particles. In this work, we have attempted to explain the transverse momentum spectra of charged hadrons formed in $pp$ collision at different energies using the Pearson statistical framework. This formalism has been proved to nicely explain the spectra of particles produced in soft processes as well hard scattering processes in a consistent manner. For this analysis, we have used the highest available range of $p_T$ published by experiments to verify the applicability of Pearson statistical framework at large $p_T$.

   hep-ph1 citation
6. 06*

   Evolution of Primordial Neutrino Helicities in Cosmic Gravitational Inhomogeneities

   Gordon Baym🇺🇸 · Jen-Chieh Peng🇺🇸

   Relic neutrinos from the Big Bang decoupled from the hot plasma predominantly in helicity eigenstates. Their subsequent propagation through gravitational inhomogeneities of the Universe alters the helicities of both Dirac and Majorana neutrinos, thus providing an independent probe of the evolving universe. We determine here the probability that relic neutrinos flip their helicity, in terms of the spectrum of density inhomogeneities measured in the Cosmic Microwave Background. As we find, for Dirac neutrinos the gravitational helicity modifications are intermediate between the effects of magnetic fields if the neutrino magnetic moment is of the magnitude predicted in the Standard Model and the much larger effects if the magnetic moment is of the scale consistent with the excess of low energy electron events seen by the XENON1T experiment. We give succinct derivations, within general relativity, of the semi-classical response of a spinning particle to a weak gravitational field in an expanding universe, and estimate the helicity modifications of neutrinos emitted by the Sun caused by the Sun's gravity.

   hep-phastro-ph.COnucl-exnucl-thPRD(2021)·21 citations
7. 07*

   Messenger inflation in gauge mediation and superWIMP dark matter

   Shinsuke Kawai🇰🇷 · Nobuchika Okada🇺🇸

   We discuss phenomenological viability of a novel inflationary model in the minimal gauge mediated supersymmetry breaking scenario. In this model, cosmic inflation is realized in the flat direction along the messenger supermultiplets and a natural dark matter candidate is the gravitino from the out-of-equilibrium decay of the bino-like neutralino at late times, which is called the superWIMP scenario. The produced gravitino is warmish and can have a large free-streaming length; thus the cusp anomaly in the small scale structure formation may be mitigated. We show that the requirement of the Standard Model Higgs boson mass to be $m_{h^0}=125.1$ GeV gives a relation between the spectrum of the cosmic microwave background and the messenger mass $M$. We find, for the e-folding number $N_e=60$, the Planck 2018 constraints (TT, TE, EE+lowE+lensing+BK15+BAO, 68% confidence level) give $M>3.64\times 10^7$ GeV. The gravitino dark matter mass is $m_{3/2}<5.8$ GeV and the supersymmetry breaking scale $\Lambda$ is found to be in the range $(1.28-1.33)\times 10^6$ GeV. Future CMB observation is expected to give tighter constraints on these parameters.

   hep-phastro-ph.COhep-thPRD(2021)·6 citations
8. 08*

   Chiral excitations of open-beauty systems

   Xiao-Yu Guo🇩🇪 · Matthias F.M. Lutz🇩🇪

   We study the scattering of open-beauty mesons and Goldstone bosons as predicted by the chiral SU(3) Lagrangian. The impact of subleading order chiral interactions to systems with $J^P=0^{+}$ and $J^P=1^{+}$ quantum numbers is worked out. We estimate the relevant low-energy coefficients from the open-charm sector, for which their values have been determined previously from sets of QCD lattice data. The leading order heavy-quark symmetry breaking effects are estimated by matching the $B$-meson ground-state chiral mass formula to the mass formula from the heavy-quark effective theory. We make refined predictions for the flavor anti-triplet and sextet resonances that are generated dynamically by coupled-channel interactions.

   hep-phhep-latPRD(2021)·2 citations
9. 09*

   A novel strategy for searching for $CP$ violations in the baryon sector

   Zhen-Hua Zhang🇨🇳 · Xin-Heng Guo🇨🇳

   Despite the large baryon-anti-baryon asymmetry in the observable Universe, the closely related phenomenon -- the violation of the combined charge and parity symmetry ($CP$V) -- has not been observed in the baryon sector in laboratories. In this paper, a new strategy for searching for $CP$V in heavy hadron multi-body decays is proposed, in which a set of novel observables measuring $CP$V in such decays -- the partial wave $CP$ asymmetries (PW$CP$As) -- are introduced. This strategy is model-independent and applicable to multi-body decays of heavy hadrons with arbitrary spin configurations in both initial and final states, and with any number of particles in the final state. It is especially applicable for $CP$V investigations in multi-body decays of heavy baryons. As applications of this strategy, we suggest to measure the PW$CP$As in some decay channels of bottom baryons such as ${\Lambda }_b^0\to p{\pi }^{-}{\pi }^{+}{\pi }^{-}$, ${\Lambda }_b\to p{K}^{-}{\pi }^{+}{\pi }^{-}$, ${\Lambda }_b^0\to p{\pi }^{-}{K}^{+}{K}^{-}$, ${\Lambda }_b^0\to \Lambda K^{+}{\pi }^{-}$, and ${\Lambda }_b^0\to p{\pi }^{-}{K}_s$.}

   hep-phhep-exJHEP(2021)·13 citations
10. 10*

    Predicting the $\sin {\varphi }_S$ Single-Spin-Asymmetry of $\Lambda$ Production off transversely polarized nucleon in SIDIS

    Yongliang Yang (Qingdao U., Qingdao)🇨🇳 · Xiaoyu Wang (Zhengzhou U., Zhengzhou)🇨🇳 · Zhun Lu (Southeast U., Nanjing)🇨🇳

    We investigate the transverse target spin asymmetry $A_{UT}^{\sin {\varphi }_S}$ for the unpolarized $\Lambda$ production in semi-inclusive deep inelastic scattering with the transverse momentum of the final-state lambda hyperon being integrated out. The asymmetry is contributed by the product of the transversity distribution function $h_1(x)$ of the nucleon and the collinear twist-3 fragmentation function $\tilde{H}(z)$ of the $\Lambda$ hyperon. The later one originates from the quark-gluon-quark correlation and is a naive time-reversal-odd function. We calculate $\tilde{H}$ of the $\Lambda$ hyperon by adopt a diquark spectator model. Using the numerical result of $\tilde{H}(z)$ and the available parametrization of $h_1(x)$ from SIDIS data, we predict the $\sin {\varphi }_S$ asymmetry in the electroproduction of the $\Lambda$ hyperon in the kinematical region of EIC, EicC and COMPASS. In the phenomenological analysis we include the evolution effect of the distribution functions and the fragmentation functions. The results show that the asymmetries for the $\Lambda$ production SIDIS process is around 0.1 and may be accessible at EIC, EicC and COMPASS. We also find that the evolution of fragmentation function can affect the size of asymmetry.

    hep-phPRD(2021)·6 citations
11. 11*

    Doubly Charged Higgs Production at Future $ep$ Colliders

    Xing-Hua Yang🇨🇳 · Zhong-Juan Yang🇨🇳

    The Higgs sector of the standard model can be extended by introducing an $SU(2{)}_L$ Higgs triplet $\Delta$ to generate the tiny neutrino masses in the framework of type-II seesaw mechanism. In this paper, we study the pair production of the introduced Higgs triplet at future $e^{-}p$ colliders. The corresponding production cross sections via vector boson fusion process at FCC-ep and ILC$\otimes$FCC are predicted, where the production of a pair of doubly charged Higgs is found to be dominant and then used to investigate the collider phenomenology of the Higgs triplet. Depending on the size of the Higgs triplet vacuum expectation value, the doubly charged Higgs may decay into a pair of same-sign charged leptons or a pair of same-sign $W$ bosons. In order to explore the discovery potential of the doubly charged Higgs at future $e^{-}p$ colliders, we discuss these two decay scenarios in detail and show respectively the detection sensitivity on the mass of the doubly charged Higgs.

    hep-phCPC(2022)·13 citations
12. 12*

    Production of GeV-scale heavy neutral leptons in 3-body decays. Comparison with the PYTHIA approach

    Volodymyr M. Gorkavenko🇺🇦 · Yuliia R. Borysenkova🇺🇦 · Mariia S. Tsarenkova🇺🇦

    Despite the undeniable success of the Standard Model of particle physics (SM), there are some phenomena that the SM can't explain. These phenomena indicate that the SM has to be modified. One of the possible ways to extend the SM is to introduce heavy neutral leptons (HNLs). To search for HNLs in intensity frontier experiments, one has to consider HNL production both in 2-body and 3-body decays of some mesons. We verified the possibility of using the parton level PYTHIA default matrix elements (without the form-factor formalism) to calculate HNL production in 3-body semileptonic decays of $B$ and $D$ mesons in the experimentally interesting mass range of the produced HNLs. We conclude that this approach is quite suitable for the estimation of the sensitivity region for HNLs in the intensity frontier experiments, provided one uses suitable parton level PYTHIA default matrix elements. Our study was driven by the usage of such an approximation by the SHiP collaboration. We conclude that in this case the parton level PYTHIA default matrix elements could have been chosen more appropriately.

    hep-phJ.Phys.G(2021)·4 citations
13. 13*

    Dynamical Phase Transitions in models of Collective Neutrino Oscillations

    Alessandro Roggero🇺🇸

    Collective neutrino oscillations can potentially play an important role in transporting lepton flavor in astrophysical scenarios where the neutrino density is large, typical examples are the early universe and supernova explosions. It has been argued in the past that simple models of the neutrino Hamiltonian designed to describe forward scattering can support substantial flavor evolution on very short time scales $t\approx \log (N)/(G_F{\rho }_{\nu })$, with $N$ the number of neutrinos, $G_F$ the Fermi constant and ${\rho }_{\nu }$ the neutrino density. This finding is in tension with results for similar but exactly solvable models for which $t\approx \sqrt{N}/(G_F{\rho }_{\nu })$ instead. In this work we provide a coherent explanation of this tension in terms of Dynamical Phase Transitions (DPT) and study the possible impact that a DPT could have in more realistic models of neutrino oscillations and their mean-field approximation.

    hep-phastro-ph.HEnucl-thPRD(2021)·54 citations
14. 14*

    QCD Analysis of Near-Threshold Photon-Proton Production of Heavy Quarkonium

    Yuxun Guo🇺🇸 · Xiangdong Ji🇺🇸 · Yizhuang Liu🇩🇪

    The near threshold photo or electroproduction of heavy vector quarkonium off the proton is studied in quantum chromodynamics. Similar to the high-energy limit, the production amplitude can be factorized in terms of gluonic Generalized Parton Distributions and the quarkonium distribution amplitude. At the threshold, the threshold kinematics has a large skewness parameter $\xi$, leading to the dominance of the spin-2 contribution over higher-spin twist-2 operators. Thus threshold production data are useful to extract the gluonic gravitational form factors, allowing studying the gluonic contributions to the quantum anomalous energy, mass radius, spin and mechanical pressure in the proton. We use the recent GlueX data on the $J/\psi$ photoproduction to illustrate the potential physics impact from the high-precision data from future JLab 12 GeV and EIC physics program.

    hep-phhep-latnucl-exnucl-thPRD(2021)·112 citations
15. 15*

    Anatomy of the dense QCD matter from canonical sectors

    Kouji Kashiwa🇯🇵 · Hiroaki Kouno🇯🇵

    We investigate the nuclear and the quark matter at finite real chemical potential (${\mu }_{\mathrm{R}}$) and low temperature from the viewpoint of the canonical sectors constructed via the imaginary chemical potential region. Based on the large $N_{\mathrm{c}}$ estimation, where $N_{\mathrm{c}}$ is the number of color, we can discuss the confinement-deconfinement nature at finite ${\mu }_{\mathrm{R}}$ from the canonical sectors. We found the expectation that the sharp change of canonical sectors at ${\mu }_{\mathrm{R}}\sim M_{\mathrm{B}}/N_{\mathrm{c}}$, where $M_{\mathrm{B}}$ is the lowest baryon mass, is happen in the large $N_{\mathrm{c}}$ regime, and it is matched with the quarkyonic picture. In addition, we discussed the color superconductivity and the chiral properties from the structure of canonical sectors. Even in the present anatomy from the canonical sectors, we can have the suitable picture for the dense QCD matter.

    hep-phhep-latPRD(2021)·5 citations
16. 16*

    EFT Diagrammatica: UV Roots of the CP-conserving SMEFT

    Supratim Das Bakshi🇮🇳 · Joydeep Chakrabortty🇮🇳 · Suraj Prakash🇮🇳 · Shakeel Ur Rahaman🇮🇳 · Michael Spannowsky🇬🇧

    Effective Field Theories are an established framework to bridge the gap between UV and low energy theories. In the context of the Standard Model, the bottom-up approach extends its operator set and thus equips us to astutely probe its observables while encapsulating indirect evidence of unknown high scale theories. While the top-down approach, on the other hand, employs functional techniques to integrate out the heavy fields from a BSM Lagrangian leading to a set of SMEFT operators. An intricate interplay of the two approaches enhances the efficacy of the SMEFT in making meaningful predictions while providing a platform for conducting a coherent comparison of new physics scenarios. However, while the bottom-up approach fails to indicate the origin of the effective operators, the top-down approach is highly dependent on the specific model assumptions of the UV theory. We, for the first time, are proposing a diagrammatic approach to establish selection criteria for the allowed heavy field representations corresponding to each SMEFT operator. This, in turn, paves the way to construct observable driven new physics models. While we take a predominantly minimalistic approach, we also highlight the necessity for non-minimal interactions for certain operators.

    hep-phhep-exhep-thJHEP(2021)·23 citations
17. 17*

    Thermal impacts on the properties of nuclear matter and young neutron star

    Ankit Kumar🇮🇳 · H. C. Das🇮🇳 · M. Bhuyan🇲🇾 · S. K. Patra🇮🇳

    We present a methodical study of the thermal and nuclear properties for the hot nuclear matter using relativistic-mean field theory. We examine the effects of temperature on the binding energy, pressure, thermal index, symmetry energy, and its derivative for the symmetric nuclear matter using temperature-dependent relativistic mean-field formalism for the well-known G2${}^{\ast }$ and recently developed IOPB-I parameter sets. The critical temperature for the liquid-gas phase transition in an asymmetric nuclear matter system has also been calculated and collated with the experimentally available data. We investigate the approach of the thermal index as a function of nucleon density in the wake of relativistic and non-relativistic formalism. The computation of neutrino emissivity through the direct Urca process for the supernovae remnants has also been performed, which manifests some exciting results about the thermal stabilization and evolution of the newly born proto-neutron star. The central temperature and the maximum mass of the proto-neutron star have also been calculated for different entropy values.

    hep-phastro-ph.HEnucl-thNPA(2021)·3 citations
18. 18*

    NRQCD analysis of charmonium production with pion and proton beams at fixed-target energies

    Chia-Yu Hsieh🇹🇼 · Yu-Shiang Lian🇹🇼 · Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇯🇵

    We present an analysis of hadroproduction of $J/\psi$ and $\psi (2S)$ at fixed-target energies in the framework of non-relativistic QCD (NRQCD). Using both pion- and proton-induced data, a new determination of the color-octet long-distance matrix elements (LDMEs) is obtained. Compared with previous results, the contributions from the $q\bar{q}$ and color-octet processes are significantly enhanced, especially at lower energies. A good agreement between the pion-induced $J/\psi$ production data and NRQCD calculations using the newly obtained LDMEs is achieved. We find that the pion-induced charmonium production data are sensitive to the gluon density of pions, and favor pion PDFs with relatively large gluon contents at large $x$.

    hep-phhep-exnucl-exChin.J.Phys.(2021)·15 citations
19. 19*

    Color charge correlations in the proton at NLO: beyond geometry based intuition

    Adrian Dumitru🇺🇸 · Heikki Mäntysaari🇫🇮 · Risto Paatelainen🇫🇮

    Color charge correlators provide fundamental information about the proton structure. In this Letter, we evaluate numerically two-point color charge correlations in a proton on the light cone including the next-to-leading order corrections due to emission or exchange of a perturbative gluon. The non-perturbative valence quark structure of the proton is modelled in a way consistent with high-$x$ proton structure data. Our results show that the correlator exhibits startlingly non-trivial behavior at large momentum transfer or central impact parameters, and that the color charge correlation depends not only on the impact parameter but also on the relative transverse momentum of the two gluon probes and their relative angle. Furthermore, from the two-point color charge correlator, we compute the dipole scattering amplitude. Its azimuthal dependence differs significantly from a impact parameter dependent McLerran-Venugopalan model based on geometry. Our results also provide initial conditions for Balitsky-Kovchegov evolution of the dipole scattering amplitude. These initial conditions depend not only on the impact parameter and dipole size vectors, but also on their relative angle and on the light-cone momentum fraction $x$ in the target.

    hep-phhep-thPLB(2021)·36 citations
20. 20*

    Novel Leptoquark Pair Production at LHC

    Ilja Doršner🇭🇷 · Svjetlana Fajfer🇸🇮 · Ajla Lejlić🇭🇷

    We introduce a novel mechanism for the leptoquark pair production at LHC that is of a $t$-channel topology and is quark-quark initiated. This mechanism operates under fairly general conditions. One of them is that the two leptoquarks in question couple to the same lepton and the other one is that the fermion numbers of these two leptoquarks differ by two. The strength of the proposed mechanism provides an alternative way to the conventional processes to efficiently constrain the parameter space of the two leptoquark scenarios at LHC whenever the aforementioned conditions are met. We accordingly present one case study to outline the physics potential of this novel production mechanism.

    hep-phhep-exJHEP(2021)·14 citations
21. 21*

    Double electron-positron pair production with two-electron capture in relativistic heavy-ion collisions

    Melek Yilmaz Sengul🇹🇷

    We calculated the cross section of double electron-positron pair production with two-electron capture for the collisions of Pb+Pb ions and we did our calculations at LHC energies. We applied a similar methodology for the calculation of bound-free electron-positron pair production. We used perturbation theory and implemented Monte Carlo integration techniques to calculate the lowest order Feynman diagrams. We also compared our double electron-positron pair production with two-electron capture cross section results obtained in the literature. These calculations may help us to learn more about strong QED.

    hep-phActa Phys.Polon.B(2021)·0 citations
22. 22*

    Double-Hit Signature of Millicharged Particles in 3D segmented neutrino detector

    Dmitry Gorbunov🇷🇺 · Igor Krasnov🇷🇺 · Yury Kudenko🇷🇺 · Sergey Suvorov🇷🇺

    We calculate the production of hypothetical millicharged particles (MCPs) of sub-GeV masses by the J-PARC proton beam in the framework of T2K and future T2HK neutrino oscillation experiments. Concentrating on the region of model parameter space, where an MCP can hit the near neutrino detector twice, we adopt this background-free signature to estimate the sensitivity of T2K and T2HK experiments to MCPs. We find that a previously inaccessible in direct searches region of charges 5$\times$$10^{-4}$-$10^{-2}$ $e$ for MCP masses 0.1-0.5 GeV can be probed.

    hep-phhep-exPLB(2021)·14 citations
23. 23*

    K0 and K+ meson electromagnetic form factors: a nonperturbative relativistic quark model versus experimental, perturbative and lattice Quantum-Chromodynamics results

    S.V. Troitsky🇷🇺 · V.E. Troitsky🇷🇺

    It has been previously shown that a particular nonperturbative constituent-quark model of hadrons describes experimental measurements of electromagnetic form factors of light charged mesons through a small number of common phenomenological parameters, matching at the same time the Quantum-Chromodynamics (QCD) asymptotics for the pi-meson form factor at large momentum transfer. Here we start with the determination of the K0 electromagnetic form factor in this approach. Precise measurement of the K0 charge radius makes it possible to constrain model parameters with high accuracy. Then, with all parameters fixed, we revisit the K+ form factor and find that it matches experimental measurements in the infrared, lattice results at moderate momentum transfer and the perturbative QCD asymptotics in the ultraviolet. In this way we obtain a narrow constraint on the K+ charge radius, <r_K+^2> = 0.403 +0.007 -0.006 fm^2, and extend the successful infrared-ultraviolet connection from pi to K mesons.

    hep-phPRD(2021)·4 citations
24. 24*

    TeV-scale vector leptoquark from Pati-Salam unification with vectorlike families

    Syuhei Iguro🇯🇵 · Junichiro Kawamura🇰🇷 · Shohei Okawa🇨🇦 · Yuji Omura🇯🇵

    In this paper, we show an explicit way to realize a TeV-scale vector leptoquark from the Pati-Salam (PS) unification with extra vectorlike families. The leptoquark mass is constrained to be heavier than PeV-scale by the measurement of a flavor violating kaon decay, $K_L\to \mu e$, in conventional models. This strong constraint can be avoided by introducing vectorlike families consistently with the quark and lepton masses and CKM and PMNS matrices. The other flavor violating processes are also suppressed. In this model, the vector leptoquark can be sufficiently light to explain the recent $b\to s\mu \mu$ anomaly, while the $b\to c\tau \nu$ anomaly is difficult to be explained due to the strong constraints from the $Z^{\prime }$ boson and vectorlike quark searches at the LHC. When the $b\to s\mu \mu$ anomaly is explained, we show that $\mathcal{O}(0.2)$ % tuning is required in the fermion matrix, the future experiments in $\mu \to e\gamma$ and $\mu$-$e$ conversions will cover the most available parameter space, and sizable neutral meson mixings, induced by the extra Higgs doublets, are unavoidable.

    hep-phhep-exPRD(2021)·30 citations
25. 25*

    Searching New Particles at Neutrino Telescopes with Quantum-Gravitational Decoherence

    Dominik Hellmann🇩🇪 · Heinrich Päs🇩🇪 · Erika Rani🇩🇪

    We discuss the interplay of wave packet decoherence and decoherence induced by quantum gravity via interactions with spacetime foam for high energy astrophysical neutrinos. In this context we point out a compelling consequence of the expectation that quantum gravity should break global symmetries, namely that quantum-gravity induced decoherence may not only be the most sensitive probe for quantum properties of spacetime, but also can provide both a powerful tool for the search for new particles, including totally decoupled backgrounds interacting only gravitationally, and at the same time a window into the intricacies of black hole information processing.

    hep-phastro-ph.HEgr-qchep-thPRD(2022)·10 citations
26. 26*

    Correlating Non-Resonant Di-Electron Searches at the LHC to the Cabibbo-Angle Anomaly and Lepton Flavour Universality Violation

    Andreas Crivellin🇨🇭 · Claudio Andrea Manzari🇨🇭 · Marc Montull🇨🇭

    In addition to the existing strong indications for lepton flavour university violation (LFUV) in low energy precision experiments, CMS recently released an analysis of non-resonant di-lepton pairs which could constitute the first sign of LFUV in high-energy LHC searches. In this article we show that the Cabibbo angle anomaly, an (apparent) violation of first row and column CKM unitarity with $\approx 3\sigma$ significance, and the CMS result can be correlated and commonly explained in a model independent way by the operator $[Q_{\ell q}^{(3)}{]}_{1111}=({\bar{\ell }}_1{\gamma }^{\mu }{\sigma }^I{\ell }_1)({\bar{q}}_1{\gamma }_{\mu }{\sigma }^I{q}_1)$. This is possible without violating the bounds from the non-resonant di-lepton search of ATLAS (which interestingly also observed slightly more events than expected in the electron channel) nor from $R(\pi )=\pi \to \mu \nu /\pi \to e\nu$. We find a combined preference for the new physics hypothesis of $4.5\sigma$ and predict $1.0004<R(\pi )<1.0009$ (95\%~CL) which can be tested in the near future with the forthcoming results of the PEN experiment.

    hep-phhep-exhep-thnucl-ex+1PRD(2021)·36 citations
27. 27*

    Fermionic Singlet Dark Matter in One-Loop Solutions to the $R_K$ Anomaly: A Systematic Study

    Mathias Becker🇩🇪 · Dominik Döring🇩🇪 · Siddhartha Karmakar🇮🇳 · Heinrich Päs🇩🇪

    We study the dark matter phenomenology of Standard Model extensions addressing the reported anomaly in the $R_K$ observable at one-loop. The article covers the case of fermionic singlet DM coupling leptophilically, quarkphilically or amphiphilically to the SM. The setup utilizes a large coupling of the new particle content to the second lepton generation to explain the $R_K$ anomaly, which in return tends to diminish the dark matter relic density. Further, dark matter direct detection experiments provide stringent bounds even in cases where the dark matter candidate only contributes a small fraction of the observed dark matter energy density. In fact, direct detection rules out all considered models as an explanation for the $R_K$ anomaly in the case of Dirac dark matter. Conversely, for Majorana dark matter, the $R_K$ anomaly can be addressed in agreement with direct detection in coannihilation scenarios. For leptophilic dark matter this region only exists for $M_{\text{DM}}\lesssim 1000\mathrm{GeV}$ and dark matter is underabundant. Quarkphilic and amphiphilic scenarios even provide narrow regions of parameter space where the observed relic density can be reproduced while offering an explanation to $R_K$ in agreement with direct detection experiments.

    hep-phEPJC(2021)·12 citations
28. 28*

    Perturbative QCD Analysis of Near Threshold Heavy Quarkonium Photoproduction at Large Momentum Transfer

    Peng Sun🇨🇳 · Xuan-Bo Tong🇨🇳 · Feng Yuan🇺🇸

    We apply perturbative QCD to investigate the near threshold heavy quarkonium photoproduction at large momentum transfer. From an explicit calculation, we show that the conventional power counting method will be modified and the three quark Fock state with nonzero orbital angular momentum dominates the near threshold production. It carries a power behavior of $1/(-t{)}^5$ for the differential cross section. We further comment on the impact of our results on the interpretation of the experiment measurement in terms of the gluonic gravitational form factors of the proton.

    hep-phhep-exnucl-exnucl-thPLB(2021)·58 citations
29. 29*

    Global Fits of Third Family Hypercharge Models to Neutral Current B-Anomalies and Electroweak Precision Observables

    B.C. Allanach🇬🇧 · J. Eliel Camargo-Molina🇸🇪 · Joe Davighi🇬🇧

    While it is known that third family hypercharge models can explain the neutral current $B-$anomalies, it was hitherto unclear whether the $Z-Z^{\prime }$ mixing predicted by such models could simultaneously fit electroweak precision observables. Here, we perform global fits of several third family hypercharge models to a combination of electroweak data and those data pertinent to the neutral current $B-$anomalies. While the Standard Model is in tension with this combined data set with a $p-$value of $.00068$, simple versions of the models (fitting two additional parameters each) provide much improved fits. The original Third Family Hypercharge Model, for example, has a $p-$value of $.065$, i.e. $\sqrt{\Delta {\chi }^2}=6.5\sigma$.

    hep-phhep-exEPJC(2021)·22 citations
30. 30*

    $A_{FB}$ in the SMEFT: precision Z physics at the LHC

    Víctor Bresó-Pla🇪🇸 · Adam Falkowski🇫🇷 · Martín González-Alonso🇪🇸

    We study the forward-backward asymmetry $A_{FB}$ in $pp\to {\ell }^{+}{\ell }^{-}$ at the Z peak within the Standard Model Effective Field Theory (SMEFT). We find that this observable provides per mille level constraints on the vertex corrections of the Z boson to quarks,which close a flat direction in the electroweak precision SMEFT fit. Moreover, we show that current $A_{FB}$ data is precise enough so that its inclusion in the fit improves significantly LEP bounds even in simple New Physics setups. This demonstrates that the LHC can compete with and complement LEP when it comes to precision measurements of the Z boson properties

    hep-phJHEP(2021)·53 citations
31. 31*

    $W^{+}{W}^{-}$ production at NNLO+PS with MiNNLO${}_{\mathrm{PS}}$

    Daniele Lombardi🇩🇪 · Marius Wiesemann🇩🇪 · Giulia Zanderighi🇩🇪

    We consider $W^{+}{W}^{-}$ production in hadronic collisions and present the computation of next-to-next-to-leading order accurate predictions consistently matched to parton showers (NNLO+PS) using the MiNNLO${}_{\mathrm{PS}}$ method. Spin correlations, interferences and off-shell effects are included by calculating the full process $pp\to e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }$. This is the first NNLO+PS calculation for $W^{+}{W}^{-}$ production that does not require an a-posteriori multi-differential reweighting. The evaluation time of the two-loop contribution has been reduced by more than one order of magnitude through a four-dimensional cubic spline interpolation. We find good agreement with the inclusive and fiducial cross sections measured by ATLAS and CMS. Both NNLO corrections and matching to parton showers are important for an accurate simulation of the $W^{+}{W}^{-}$ signal, and their matching provides the best description of fully exclusive $W^{+}{W}^{-}$ events to date.

    hep-phhep-exJHEP(2021)·54 citations
32. 32*

    Dipole Radiation and Beyond from Axion Stars in Electromagnetic Fields

    Mustafa A. Amin🇺🇸 · Andrew J. Long🇺🇸 · Zong-Gang Mou🇺🇸 · Paul Saffin🇬🇧

    We investigate the production of photons from coherently oscillating, spatially localized clumps of axionic fields (oscillons and axion stars) in the presence of external electromagnetic fields. We delineate different qualitative behaviour of the photon luminosity in terms of an effective dimensionless coupling parameter constructed out of the axion-photon coupling, and field amplitude, oscillation frequency and radius of the axion star. For small values of this dimensionless coupling, we provide a general analytic formula for the dipole radiation field and the photon luminosity per solid angle, including a strong dependence on the radius of the configuration. For moderate to large coupling, we report on a non-monotonic behavior of the luminosity with the coupling strength in the presence of external magnetic fields. After an initial rise in luminosity with the coupling strength, we see a suppression (by an order of magnitude or more compared to the dipole radiation approximation) at moderately large coupling. At sufficiently large coupling, we find a transition to a regime of exponential growth of the luminosity due to parametric resonance. We carry out 3+1 dimensional lattice simulations of axion electrodynamics, at small and large coupling, including non-perturbative effects of parametric resonance as well as backreaction effects when necessary. We also discuss medium (plasma) effects that lead to resonant axion to photon conversion, relevance of the coherence of the soliton, and implications of our results in astrophysical and cosmological settings.

    hep-phastro-ph.COJHEP(2021)·45 citations
33. 33*

    Axion Haloscope Array With $\mathcal{P}\mathcal{T}$ Symmetry

    Yifan Chen🇨🇳 · Minyuan Jiang🇨🇳 · Yiqiu Ma🇨🇳 · Jing Shu🇨🇳 · Yuting Yang🇨🇳

    We generalize the recently proposed $\mathcal{P}\mathcal{T}$-symmetric axion haloscope to a larger array with more $\mathcal{P}\mathcal{T}$-symmetric structures. By broadening the response bandwidth of the signal without increasing the readout noise, the optimized scan rate of the axion haloscope is significantly enhanced, as well as is the signal power. Furthermore, we show that the robustness of the detector towards the variations of the array coupling is the strongest when a binary tree structure is introduced which contains a largely enhanced $\mathcal{P}\mathcal{T}$ symmetry. The multiple allowed probing sensors can further increase the scan rate by a factor of the sensors' number due to the correlation of the signals. This type of array can strongly boost the search for an axion compared to single-mode resonant detection. The enhancement to the scan rate becomes the most manifest when applied to the proposed detection using a superconducting radio-frequency cavity with an ac magnetic field where most of the parameter space of the QCD axion above kHz can be probed.

    hep-phhep-exquant-phPRResearch(2022)·17 citations
34. 34*

    Multi-TeV Signals of Baryogenesis in Higgs Troika Model

    Hooman Davoudiasl🇺🇸 · Ian M. Lewis🇺🇸 · Matthew Sullivan🇺🇸

    A modest extension of the Standard Model by two additional Higgs doublets - the Higgs Troika Model - can provide a well-motivated scenario for successful baryogenesis if neutrinos are Dirac fermions. Adapting the "Spontaneous Flavor Violation" framework, we consider a version of the Troika model where light quarks have significant couplings to the new multi-TeV Higgs states. Resonant production of new scalars leading to di-jet or top-pair signals are typical predictions of this setup. The initial and final state quarks relevant to the collider phenomenology also play a key role in baryogenesis, potentially providing direct access to the relevant early Universe physics in high energy experiments. Viable baryogenesis generally prefers some hierarchy of masses between the observed and the postulated Higgs states. We show that there is a complementarity between direct searches at a future 100 TeV $pp$ collider and indirect searches at flavor experiments, with both sensitive to different regions of parameter space relevant for baryogenesis. In particular, measurements of $D-\bar{D}$ mixing at LHCb probe much of the interesting parameter space. Direct and indirect searches can uncover the new Higgs states up to masses of $\mathcal{O}(10)$ TeV, thereby providing an impressive reach to investigate this model.

    hep-phhep-exPRD(2021)·18 citations
35. 35*

    Global interpretation of LHC indications within the Georgi-Machacek Higgs model

    François Richard🇫🇷

    Following various LHC indications for new scalars, an interpretation of these is given in terms of the Georgi-Machacek (GM) model. On top of the confirmed SM Higgs boson, there are indications for a light Higgs at 96 GeV, for a CP-odd boson at 400 GeV, A(400), and for a heavy Higgs boson at 660 GeV. An extension of the GM is needed to interpret the fermion couplings of A(400). Potentially interesting deviations are also observed in the ttW cross-section measurement, which naturally fit into this picture. None of them crosses the fatidic five s.d. evidence but the addition of these effects, consistent with GM, suggest that there are good hopes for solid discoveries at HL-LHC, which should boost the motivation for future machines. The GM model also provides a useful framework to estimate the rates expected for various channels at an $e^{+}{e}^{-}$ collider, together with the range of energies needed. ILC performances are used for a quantitative estimate of these rates for the prominent channels.

    hep-phhep-ex8 citations
36. 36*

    Bi-metric Universe with Matter

    Carlos Maldonado🇨🇱 · Fernando Mendez🇨🇱

    We analyze the early stage of evolution of a universe with two scale factors proposed in [1] when matter is present. The scale factors describe two causally disconnected patches of the universe interacting trough a non-trivial Poisson bracket structure in the momentum sector characterized by one parameter \kappa. We studied two scenarios in which one of the patches is always filled with relativistic matter while the other contains relativistic matter in one case, and non-relativistic matter in the second case. By solving numerically the set of equations governing the dynamics, we found that the energy content of one sector drains to the other and from here it is possible to constraint the deformation parameter \kappa by imposing that the decay of the energy density happens, at most, at the Big Bang Nucleosynthesis temperature in order to return to the usual behavior of radiation. The relation with Non Standard Cosmologies is also addressed.

    ↳ gr-qcastro-ph.COhep-phPRD(2021)·7 citations
37. 37*

    Lattice QCD calculation of $K\to \ell {\nu }_{\ell }{\ell }^{\prime +}{\ell }^{\prime -}$ decay width

    Xin-Yu Tuo🇨🇳 · Xu Feng🇨🇳 · Lu-Chang Jin🇺🇸 · Teng Wang🇨🇳

    We develop a methodology for the computation of the $K\to \ell {\nu }_{\ell }{\ell }^{\prime +}{\ell }^{\prime -}$ decay width using lattice QCD and present an exploratory study here. We use a scalar function method to account for the momentum dependence of the decay amplitude and adopt the infinite volume reconstruction method to reduce the systematic errors such as the temporal truncation effects and the finite-volume effects. We then perform a four-body phase-space integral to obtain the decay width. The only remaining technical problem is the possible power-law finite-volume effects associated with the process of $K\to \pi \pi \ell {\nu }_{\ell }\to \ell {\nu }_{\ell }{\ell }^{\prime +}{\ell }^{\prime -}$, where the intermediate state involves multiple hadrons. In this work, we use a gauge ensemble of twisted mass fermion with a pion mass $m_{\pi }=352$ MeV and a nearly-physical kaon mass. At this kinematics, the $\pi \pi$ in the intermediate state cannot be on shell simultaneously as $2m_{\pi }>m_K$ and the finite-volume effects associated with $\pi \pi$ state are exponentially suppressed. Using the developed methods mentioned above, we calculate the branching ratios for four channels of $K\to \ell {\nu }_{\ell }{\ell }^{\prime +}{\ell }^{\prime -}$, and obtain the results comparable to the experimental measurements and ChPT predictions. Our work demonstrates the capability of lattice QCD to improve Standard Model prediction in $K\to \ell {\nu }_{\ell }{\ell }^{\prime +}{\ell }^{\prime -}$ decay width.

    ↳ hep-lathep-exhep-phPRD(2022)·29 citations
38. 38*

    Quadratic Gravity and Restricted Weyl Symmetry

    Arata Kamimura🇯🇵 · Ichiro Oda🇯🇵

    We investigate the relationship between quadratic gravity and a restricted Weyl symmetry where a gauge parameter $\Omega (x)$ of Weyl transformation satisfies a constraint $\square \Omega =0$ in a curved space-time. First, we briefly review a model with a restricted gauge symmetry on the basis of QED where a $U(1)$ gauge parameter $\theta (x)$ obeys a similar constraint $\square \theta =0$ in a flat Minkowski space-time, and explain that the restricted gauge symmetry removes one on-shell mode of gauge field, which together with the Feynman gauge leaves only two transverse polarizations as physical states. Next, it is shown that the restricted Weyl symmetry also eliminates one component of a dipole field in quadratic gravity around a flat Minkowski background, leaving only a single scalar state. Finally, we show that the restricted Weyl symmetry cannot remove any dynamical degrees of freedom in static background metrics by using the zero-energy theorem of quadratic gravity. This fact also holds for the Euclidean background metrics without imposing the static condition.

    ↳ hep-thgr-qchep-phMod.Phys.Lett.A(2021)·11 citations
39. 39*

    Magneto-vortical Effect in Strong Magnetic Field

    Shu Lin🇨🇳 · Lixin Yang🇨🇳

    We develop covariant chiral kinetic theory with Landau level basis. We use it to investigate a magnetized plasma with a transverse electric field and a steady vorticity as perturbations. After taking into account vacuum shift in the latter case, we find the resulting current and stress tensor in both cases can be matched consistently with constitutive equations of magnetohydrodynamics. We find the solution in the vorticity case contains both shifts in temperature and chemical potential as well as excitations of the lowest Landau level states. The solution gives rise to an vector charge density and axial current density. The vacuum parts coming from both shifts and excitations agree with previous studies and the medium parts coming entirely from excitations leads to a new contribution to vector charge and axial current density consistent with standard chiral vortical effect.

    ↳ nucl-thcond-mat.mes-hallhep-phJHEP(2021)·15 citations
40. 40*

    Adiabatic Duality: Duality of cosmological models with varying slow-roll parameter and sound speed

    Jiaming Shi🇨🇳 · Zheng Fang🇨🇳 · Taotao Qiu🇨🇳

    There have been thousands of cosmological models for our early universe proposed in the literature, and many of them claimed to be able to give rise to scale-invariant power spectrum as was favored by the observational data. It is thus interesting to think about whether there are some relations among them, e.g., the duality relation. In this paper, we investigate duality relations between cosmological models in framework of general relativity (GR) , not only with varying slow-roll parameter $ϵ$, but also with sound speed $c_s$, which can then be understood as "adiabatic duality". Several duality relationships are formulated analytically and verified numerically. We show that models with varying $ϵ$ and constant $c_s$ can be dual in scalar spectral index, but not tensor one. On the other hand, allowing both $ϵ$ and $c_s$ to vary can make models dual in both scalar and tensor spectral indices.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2021)·2 citations
41. 41*

    Prospects for measuring dark matter microphysics with observations of dwarf spheroidal galaxies

    Eric J. Baxter🇺🇸 · Jason Kumar🇺🇸 · Andrew B. Pace🇺🇸 · Jack Runburg🇺🇸

    Dark matter annihilation in dwarf spheroidal (dSph) galaxies near the Milky Way has the potential to produce a detectable signature in gamma-rays. The amplitude of this signal depends on the dark matter density in a dSph, the dark matter particle mass, the number of photons produced in an annihilation, and the possibly velocity-dependent dark matter annihilation cross section. We argue that if the amplitude of the annihilation signal from multiple dSphs can be measured, it is possible to determine the velocity-dependence of the annihilation cross section. However, we show that doing so will require improved constraints on the dSph density profiles, including control of possible sources of systematic uncertainty. Making reasonable assumptions about future improvements, we make forecasts for the ability of current and future experiments -- including Fermi, CTA and AMEGO -- to constrain the dark matter annihilation velocity dependence.

    ↳ astro-ph.COastro-ph.HEhep-phJCAP(2021)·7 citations
42. 42*

    Källén-Lehmann Spectral Representation of the Scalar SU(2) Glueball

    David Dudal🇧🇪 · Orlando Oliveira🇵🇹 · Martin Roelfs🇧🇪

    The estimation of the Källén-Lehmann spectral density from gauge invariant lattice QCD two point correlation functions is proposed, and explored via an appropriate inversion method. As proof of concept the SU(2) glueball spectrum for the quantum numbers $J^{PC}=0^{++}$ is investigated for various values of the lattice spacing. The spectral density and the glueball spectrum are estimated using the published data of arXiv:1910.07756. Our estimates for the ground state mass are in good agreement with the traditional approach published therein, which is based on the large time exponential behaviour of the correlation functions. Furthermore, the spectral density also contains hints of excites states in the spectrum.

    ↳ hep-lathep-phEPJC(2022)·11 citations
43. 43*

    Fuzzball Shadows: Emergent Horizons from Microstructure

    Fabio Bacchini🇧🇪 · Daniel R. Mayerson🇫🇷 · Bart Ripperda🇺🇸 · Jordy Davelaar🇺🇸 · Héctor Olivares🇳🇱 · Thomas Hertog🇧🇪 · Bert Vercnocke🇧🇪

    We study the physical properties of four-dimensional, string-theoretical, horizonless "fuzzball" geometries by imaging their shadows. Their microstructure traps light rays straying near the would-be horizon on long-lived, highly redshifted chaotic orbits. In fuzzballs sufficiently near the scaling limit this creates a shadow much like that of a black hole, while avoiding the paradoxes associated with an event horizon. Observations of the shadow size and residual glow can potentially discriminate between fuzzballs away from the scaling limit and alternative models of black compact objects.

    ↳ hep-thastro-ph.HEgr-qchep-phPRL(2021)·68 citations
44. 44*

    Persistent homology analysis for dense QCD effective model with heavy quarks

    Kouji Kashiwa🇯🇵 · Takehiro Hirakida🇯🇵 · Hiroaki Kouno🇯🇵

    The isospin chemical potential region is known as the sign-problem free region of quantum chromodynamics (QCD). In this paper, we introduce the isospin chemical potential to the three-dimensional three-state Potts model to mimic the dense QCD; e.g., the QCD effective model with heavy quarks at finite density. We call it as QCD-like Potts model. The QCD-like Potts model does not have the sign problem, but we can expect that it shares some properties with QCD. Since we can obtain the non-approximated Potts spin configuration at finite isospin chemical potential where the simple Metropolis algorithm can work, we perform the persistent homology analysis towards exploring the dense spatial structure of QCD. We show that the averaged birth-death ratio has the same information with the Polyakov loop, but the maximum birth-death ratio has additional information near the phase transition.

    ↳ hep-lathep-phSymmetry(2022)·15 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.