Tue·May 19, 2020Tuesday·May 19, 2020

1. 01*

   Low energy pion-${\Lambda }_b$ interaction

   Marcelo G. L. Nogueira-Santos🇧🇷 · Celso C. Barros Jr🇧🇷

   In this work we study the low energy pion-${\Lambda }_b$ interaction considering effecective chiral Lagrangians that include pions, baryons and the corresponding resonances. Interactions mediated by a $\sigma$ meson exchange are also considered. The scattering amplitudes are calculated and then we determine the angular distributions and polarizations.

   hep-phEPJC(2020)·2 citations
2. 02*

   Neutrino oscillations as many-particle induced interference between distinguishable particles

   Alejandro Cabo Montes de Oca🇨🇺 · Nana Geraldine Cabo Bizet🇲🇽

   We investigate the causes of the curious property of neutrino oscillations of looking as an interference between fully distinguishable particles. The sources of this effect are identified as to be determined by the many particle nature of space of states of the quantum field theory. It is firstly underlined that in order to explain the observed oscillations, the neutrino subspace of states should not be interpreted as the direct product of the three neutrinos Fock spaces, which is equivalent to imposing a superselection rule. Further, it is argued that the linear completion of such a direct product space of states permits to describe the measured oscillations. Thus, the space of states of te Standard Model (SM) should be interpreted as the linear completion of the direct product of all the Fock spaces (boson or fermions ones) associated to the distinguishable particles. Then, it follows that the neutrino oscillations are determined as interference between independent particles, which are generated by states being outside the direct product of the neutrino Fock spaces. This interpretation seems to imply a large amount of interference observations between distinguishable particles in Particle as well as in Condensed Matter Physics. For seeking clearness, the discussion is done in the framework of a simple Quantum Field Theory (QFT) model of two relativistic free massive neutrinos.

   hep-phhep-th5 citations
3. 03*

   Investigating the inclusive transverse spectra in high-energy $pp$ collisions in the context of geometric scaling framework

   L. S. Moriggi🇧🇷 · G. M. Peccini🇧🇷 · M. V. T. Machado🇧🇷

   The presence of geometric scaling within the $p_T$ spectra of produced hadrons at high energy $pp$ collisions using small-$x$ $k_T$-factorization is investigated. It is proposed a phenomenological parameterization for the unintegrated gluon distribution in the scaling range which reproduces the features of the differential cross section both in the saturated and dilute perturbative QCD regimes. As the saturation scale acts as an effective regulator of the infrared region (IR), the extension of the model to quantities usually associated to soft physics is studied. The approach is applied to compute the average $p_T$ and the rapidity distribution of produced gluons at high energies.

   hep-phPRD(2020)·38 citations
4. 04*

   Precise predictions for boosted Higgs production

   K. Becker🇩🇪 · F. Caola🇬🇧 · A. Massironi🇨🇭 · B. Mistlberger🇺🇸 · P. F. Monni🇨🇭 · X. Chen🇨🇭 · S. Frixione🇮🇹 · T. Gehrmann🇨🇭 · N. Glover🇬🇧 · K. Hamilton🇬🇧 · A. Huss🇨🇭 · S. P. Jones🇨🇭 and 11 other authors

   Inclusive Higgs boson production at large transverse momentum is induced by different production channels. We focus on the leading production through gluon fusion, and perform a consistent combination of the state of the art calculations obtained in the infinite-top-mass effective theory at next-to-next-to-leading order (NNLO) and in the full Standard Model (SM) at next-to-leading order (NLO). We thus present approximate QCD predictions for this process at NNLO, and a study of the corresponding perturbative uncertainties. This calculation is then compared with those obtained with commonly used event generators, and we observe that the description of the considered kinematic regime provided by these tools is in good agreement with state of the art calculations. Finally, we present accurate predictions for other production channels such as vector boson fusion, and associated production with a gauge boson, and with a $t\bar{t}$ pair. We find that, at large transverse momentum, the contribution of other production modes is substantial, and therefore must be included for a precise theory prediction of this observable.

   hep-phhep-exSciPost Phys.Core(2024)·57 citations
5. 05*

   Model identification in ${\mu }^{-}\to e^{-}$ conversion with invisible boson emission using muonic atoms

   Yuichi Uesaka🇯🇵

   In this article, we investigate the ${\mu }^{-}\to e^{-}X$ process in a muonic atom, where $X$ is a light neutral boson. By calculating the spectrum of the emitted electron for several cases, we discuss the model-discriminating power of the process. We report the strong model dependence of the spectrum near a high-energy endpoint. Our findings show that future experiments using muonic atoms are helpful to identify the properties of exotic bosons.

   hep-phhep-exPRD(2020)·14 citations
6. 06*

   Three-boson bound states in Minkowski space with contact interactions

   E. Ydrefors🇧🇷 · J.H. Alvarenga Nogueira🇧🇷 · V.A. Karmanov🇷🇺 · T. Frederico🇧🇷

   The structure of the three-boson bound state in Minkowski space is studied for a model with contact interaction. The Faddeev-Bethe-Salpeter equation is solved both in Minkowski and Euclidean spaces. The results are in fair agreement for comparable quantities, like the transverse amplitude obtained when the longitudinal constituent momenta of the light-front valence wave function are integrated out. The Minkowski space solution is obtained numerically by using a recently proposed method based on the direct integration over the singularities of the propagators and interaction kernel of the four-dimensional integral equation. The complex singular structure of the Faddeev components of the Bethe-Salpeter vertex function for space and time-like momenta in an example of a Borromean system is investigated in detail. Furthermore, the transverse amplitude is studied as a mean to access the double-parton transverse momentum distribution. Following that, we show that the two-body short-range correlation contained in the valence wave function is evidenced when the pair has a large relative momentum in a back-to-back configuration, where one of the Faddeev components of the Bethe-Salpeter amplitude dominates over the others. In this situation a power-law behavior is derived and confirmed numerically.

   hep-phPRD(2020)·10 citations
7. 07*

   Extending low energy effective field theory with a complete set of dimension-7 operators

   Yi Liao (Nankai Uni. and CHEP, Peking Uni.)🇨🇳 · Xiao-Dong Ma (Taiwan Uni.)🇹🇼 · Quan-Yu Wang (Nankai Uni.)🇨🇳

   We present a complete and independent set of dimension-7 operators in the low energy effective field theory (LEFT) where the dynamical degrees of freedom are the standard model five quarks and all of the neutral and charged leptons. All operators are non-Hermitian and are classified according to their baryon ($\Delta B$) and lepton ($\Delta L$) numbers violated. Including Hermitian-conjugated operators, there are in total $3168$, $750$, $588$, $712$ operators with $(\Delta B,\Delta L)=(0,0)$, $(0,\pm 2)$, $(\pm 1,\mp 1)$, $(\pm 1,\pm 1)$ respectively. We perform the tree-level matching with the standard model effective field theory (SMEFT) up to dimension-7 (dim-7) operators in both LEFT and SMEFT. As a phenomenological application we study the effective neutrino-photon interactions due to dim-7 lepton number violating operators that are induced and much enhanced at one loop from dim-6 operators that in turn are matched from dim-7 SMEFT operators. We compare the cross sections of various neutrino-photon scattering with their counterparts in the standard model and highlight the new features. Finally we illustrate how these effective interactions could arise from ultraviolet completion.

   hep-phJHEP(2020)·80 citations
8. 08*

   Leptogenesis due to oscillating Higgs field

   Seishi Enomoto🇨🇳 · Chengfeng Cai🇨🇳 · Zhao-Huan Yu🇨🇳 · Hong-Hao Zhang🇨🇳

   We propose a new leptogenesis scenario in which the lepton asymmetry and matter particles are simultaneously generated due to the coherent oscillating Higgs background. To demonstrate the possibility of our scenario, we consider the type-I seesaw model as an illuminating example and show the numerical analysis. In order to generate the required lepton number $|n_L/s|=2.4\times 10^{-10}$, we find that the scales of the Higgs background oscillation and the lightest right-handed neutrinos mass are required to be higher than $10^{14}$ GeV

   hep-phEPJC(2020)·12 citations
9. 09*

   Beyond SM Physics and searches for SUSY at the LHC

   Dris Boubaa🇩🇿 · Gaber Faisel🇹🇷 · Shaaban Khalil🇪🇬

   This is the written version of a talk given by S.K. at the $10^{th}$ International Conference on High Energy and Astroparticle, Constantine, Algeria. We briefly review the Standard Model (SM) and the major evidences and main direction of physics beyond the SM (BSM). We introduce supersymmetry, as one of the well-motivated BSM. Basic introduction to Minimal Supersymmetric Standard Model (MSSM) is given. We analyze the thermal relic abundance of lightest neutralino, which is the Lightest Supersymmetric Particle (LSP) in the MSSM. We show that the combined Large Hadron Collider (LHC) and relic abundance constraints rule out most of the MSSM parameter space except a very narrow region. We also review non-minimal SUSY model, based on the gauge group $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y\times U(1{)}_{B-L}$ (BLSSM), where an Inverse Seesaw mechanism of light neutrino mass generation is naturally implemented. The phenomenological implications of this type of model at the Large Hadron Collider (LHC) are analyzed.

   hep-ph5 citations
10. 10*

    Rare two-body decays of the top quark into a bottom meson plus an up or charm quark

    David d'Enterria🇨🇭 · Hua-Sheng Shao🇫🇷

    Rare two-body decays of the top quark into a neutral bottom-quark meson plus an up- or charm-quark: $t\to {\overline{B}}^0+u,c$; $t\to {\overline{B}}_s^0+c,u$; and $t\to {\rm Y}(nS)+c,u$, are studied for the first time. The corresponding partials widths are computed at leading order in the non-relativistic QCD framework. The sums of all two-body branching ratios amount to $\mathcal{B}(t\to {\overline{B}}^0+\mathrm{jet})\approx \mathcal{B}(t\to {\overline{B}}_s^0+\mathrm{jet})\approx 4.2\cdot 10^{-5}$ and $\mathcal{B}(t\to {\rm Y}(nS)+\mathrm{jet})\approx 2\cdot 10^{-9}$, respectively. The feasibility to observe the $t\to {\overline{B}}_{(s)}^0+\mathrm{jet}$ decay is estimated in top-pair events produced in proton-proton collisions at $\sqrt{s}=14,100$ TeV at the LHC and FCC, respectively. Combining many exclusive hadronic ${\overline{B}}_{(s)}^0$ decays, with $J/\psi$ or $D^{0,\pm }$ final states, about 50 (16000) events are expected in 3 (20) ab${}^{-1}$ of integrated luminosity at the LHC (FCC), after typical selection criteria, acceptance, and efficiency losses. An observation of the two-body top-quark decay can also be achieved in the interesting $t\to b(\mathrm{jet})+\mathrm{c}(\mathrm{jet})$ dijet final state, where the ${\overline{B}}_{(s)}^0$ decay products are reconstructed as a jet, with 5300 and 1.4 million signal events above backgrounds expected after selection criteria at the LHC and FCC, respectively. Such unique final states provide a new direct method to precisely measure the top-quark mass via simple 2-body invariant mass analyses.

    hep-phhep-exnucl-thJHEP(2020)·3 citations
11. 11*

    Weak B Decays into Orbitally Excited Charmed Mesons

    J. Segovia🇪🇸 · C. Albertus🇪🇸 · D.R. Entem🇪🇸 · F. Fernández🇪🇸 · E. Hernández🇪🇸 · M.A. Pérez-García🇪🇸

    The BaBar Collaboration has recently reported branching fractions for semileptonic decays of the $B$ meson into final states with charged and neutral $D_1(2420)$ and $D_2^{\ast }(2460)$, two narrow orbitally excited charmed mesons. We evaluate these branching fractions within the framework of a constituent quark model in two steps, one which involves a semileptonic decay and the other one mediated by a strong process. Our results are in agreement with the experimental data.

    hep-pheConf(2011)·0 citations
12. 12*

    Microscopic Model of Charmonium Strong Decays

    J. Segovia🇪🇸 · D.R. Entem🇪🇸 · F. Fernández🇪🇸

    Although the spectra of heavy quarkonium systems has been successfully explained by certain QCD motivated potential models, their strong decays are difficult to deal with. We perform a microscopic calculation of charmonium strong decays using the same constituent quark model which successfully describes the $c\bar{c}$ meson spectrum. We compare the numerical results with the ${}^3{P}_0$ and the experimental data. Comparison with other predictions from similar models are included.

    hep-pheConf(2011)·0 citations
13. 13*

    Aspects on Effective Theories and the QCD transition

    Angel Gómez Nicola🇪🇸

    We review recent advances in the understanding of the Quantum Chromodynamics (QCD) transition and its nature, paying special attention to the analysis of chiral symmetry restoration within different approaches based on effective theories. After presenting some of the main aspects of the current knowledge of the phase diagram from the theoretical, experimental and lattice sides, we discuss some recent problems where approaches relying on effective theories have been particularly useful. In particular, the combination of ideas such as Chiral Perturbation Theory, unitarity and Ward Identities allows us to describe successfully several observables of interest. This is particularly relevant for quantities expected to be dominated by the light meson components of the hadron gas such as the scalar and topological susceptibilities. In addition, ward identities and effective Lagrangians provide systematic results regarding chiral and $U(1{)}_A$ partner degeneration properties which are of great importance for the interplay between those two transitions and the nature of chiral symmetry restoration. Special attention is paid to the connection of this theoretical framework with lattice simulations.

    hep-phSymmetry(2020)·7 citations
14. 14*

    Observable Signatures of Scotogenic Dirac Model

    Shu-Yuan Guo🇨🇳 · Zhi-Long Han🇨🇳

    In this work, we make a detailed discussion on the phenomenology of the scotogenic Dirac model, which could accommodate the Dirac neutrino mass and dark matter. We have studied the LFV processes in this model, which are mediated by the charged scalar ${\varphi }^{\pm }$ and heavy fermions $N_i$. The experimental bounds, especially given by decays $\mu \to e\gamma$ and $\mu \to 3e$, have put severe constraints on Yukawa $y_{\Phi }$ and masses $m_{N1}$, $m_{\varphi }$. We select the heavy fermion $N_1$ as dark matter candidate and find the correct relic density is basically by annihilating through another Yukawa $y_{\chi }$. After satisfying LFV and dark matter relic density constraints, we consider the indirect detections of dark matter annihilating into leptons. But the constraints are relatively loose. Then we make a detailed discussion on the dark matter direct detections. Although two Yukawa can both contribute to the direct detection processes, more attention has been paid on the $y_{\Phi }$-related processes as the $y_{\chi }$-related process is bounded loosely. The current and future direct detection experiments have been used to set constraints on the Yukawas and masses. The current direct detections bounds are relatively loose and can barely exclude more parameter region beyond the LFV. For the future direct detection experiments, the excluding capacities can be improved due to larger exposures. The detecting capabilities in the large mass region have not been weakened as the existence of mass enhancement from the magnetic dipole operator ${\mathcal{O}}_{mag.}$. At last, we briefly discuss the collider signal searching in this model, the most promising signature is pair produced ${\varphi }^{+}{\varphi }^{-}$ and decay into signal of ${\ell }^{+}{\ell }^{-}+/E_T$. The exclusion limits from collider on $m_{N1}$ and $m_{\varphi }$ have provided a complementary detecting capability compared to the LFV and dark matter detections.

    hep-phJHEP(2020)·35 citations
15. 15*

    Searching for lepton flavor violating decays tau to Pl in Minimal R-symmetric Supersymmetric Standard Model

    Ke-Sheng Sun🇨🇳 · Tao Guo🇨🇳 · Wei Li🇨🇳 · Xiu-Yi Yang🇨🇳 · Shu-Min Zhao🇨🇳

    We analyze the lepton flavor violating decays $\tau \to Pl$ ($P=\pi ,\eta ,{\eta }^{\prime };l=e,\mu$) in the scenario of the minimal R-symmetric supersymmetric standard model. The prediction on the branching ratios BR$(\tau \to Pe)$ and BR$(\tau \to P\mu )$ is affected by the mass insertion parameters ${\delta }^{13}$ and ${\delta }^{23}$, respectively. These parameters are constrained by the experimental bounds on the branching ratios BR($\tau \to e(\mu )\gamma$) and BR($\tau \to 3e(\mu )$). The result shows $Z$ penguin dominates the prediction on BR($\tau \to Pl$) in a large region of the parameter space. The branching ratios for BR($\tau \to Pl$) are predicted to be, at least, five orders of magnitude smaller than present experimental bounds and three orders of magnitude smaller than future experimental sensitivities.

    hep-phEPJC(2020)·6 citations
16. 16*

    Leptophobic $Z^{\prime }$ bosons in the secluded UMSSM

    Mariana Frank🇨🇦 · Yaşar Hiçyılmaz🇬🇧 · Stefano Moretti🇬🇧 · Özer Özdal🇨🇦

    We perform a comprehensive analysis of the secluded UMSSM model, consistent with present experimental constraints. We find that in this model the additional $Z^{\prime }$ gauge boson can be leptophobic without resorting to gauge kinetic mixing and, consequently, also $d$-quark-phobic, thus lowering the LHC bounds on its mass. The model can accommodate very light singlinos as DM candidates, consistent with present day cosmological and collider constraints. Light charginos and neutralinos are responsible for muon anomalous magnetic predictions within 1$\sigma$ of the measured experimental value. Finally, we look at the possibility that a lighter $Z^{\prime }$, expected to decay mainly into chargino pairs and followed by the decay into lepton pairs, could be observed at 27 TeV.

    hep-phPRD(2020)·10 citations
17. 17*

    Two-photon decays and transition form factors of ${\pi }^0$, $\eta$, and ${\eta }^{\prime }$ in large-$N_c$ chiral perturbation theory

    Patricia Bickert🇩🇪 · Stefan Scherer🇩🇪

    We present a calculation of $P\to {\gamma }^{(\ast )}{\gamma }^{(\ast )}$ processes, where $P={\pi }^0,\eta ,{\eta }^{\prime }$, at the one-loop level up to and including next-to-next-to-leading order (NNLO) in large-$N_c$ chiral perturbation theory. The results are numerically evaluated successively at LO, NLO, and NNLO. The appearing low-energy constants are determined through fits to the available experimental data. We investigate the decay widths to real photons, the single-virtual transition form factors, and the widths of $P\to \gamma l^{+}{l}^{-}$, where $l=e,\mu$. Furthermore, we provide results for the slopes and curvatures of the transition form factors.

    hep-phnucl-exnucl-thPRD(2020)·16 citations
18. 18*

    Statistical Behavior of Lepton Pair Spectrum in Drell-Yan Process and Signal from Quark-Gluon Plasma in High Energy Collisions

    Xu-Hong Zhang🇨🇳 · Fu-Hu Liu🇨🇳

    We analyze the transverse momentum ($p_T$) spectra of lepton pairs ($\ell \bar{\ell }$) generated in the Drell-Yan process, as detected in proton-nucleus (pion-nucleus) and proton-(anti)proton collisions by ten collaborations over a center-of-mass energy ($\sqrt{s_{NN}}$ or $\sqrt{s}$ if in a simplified form) range from $\sim 20$ GeV to above 10 TeV. Three types of probability density functions (the convolution of two Lévy-Tsallis functions, the two-component Erlang distribution, and the convolution of two Hagedorn functions) are utilized to fit and analyze the $p_T$ spectra. The fit results are approximately in agreement with the collected experimental data. Consecutively, we obtained the variation law of related parameters as a function of $\sqrt{s}$ and invariant mass ($Q$). In the fit procedure, a given Lévy-Tsallis (or Hagedorn) function can be regarded as the probability density function of transverse momenta contributed by a single quark ($q$) or anti-quark ($\bar{q}$). The Drell-Yan process is then described by the statistical method.

    hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2021)·1 citation
19. 19*

    $Z_0(57)$ and $E(38)$: possible surprises in the Standard Model

    Eef van Beveren🇵🇹 · George Rupp🇵🇹

    With the reported observation of the Higgs boson at the LHC, the Standard Model of particle physics seems to be complete now as for its particle content. However, several experimental data at low and intermediate energies indicate that there may be two surprises. First we propose a tentative new boson $Z_0(57)$, with a mass of about 57 GeV, on the basis of small enhancements we observe in several experiments, using recent data obtained at the LHC as well as much older ones from LEP. If confirmed, we interpret this new particle as a pseudoscalar or scalar partner of a composite $Z$ vector boson. Secondly, we advocate the existence of a very light spinless boson $E(38)$, probably a scalar, with a mass of 38 MeV and decaying into two photons. Theoretical arguments and experimental signals supporting such a novel light boson will be presented, including a recent direct experimental confirmation at the Joint Institute for Nuclear Research in Dubna.

    hep-phhep-exActa Phys.Polon.Supp.(2021)·5 citations
20. 20*

    Solutions to Problems at Les Houches Summer School on EFT

    Marcel Balsiger🇨🇭 · Marios Bounakis🇬🇧 · Mehdi Drissi🇫🇷 · John Gargalionis🇦🇺 · Erik Gustafson🇺🇸 · Greg Jackson🇨🇭 · Matthew Leak🇬🇧 · Christopher Lepenik🇦🇹 · Scott Melville🇬🇧 · Daniel Moreno🇪🇸 · Michele Tammaro🇺🇸 · Selim Touati🇫🇷 · Timothy Trott🇺🇸

    This work details worked solutions to the various problems set by the lecturers during the course of the Les Houches summer school 2017 on effective field theories in particle physics and cosmology.

    hep-phgr-qcnucl-thLes Houches Lect.Notes(2020)·3 citations
21. 21*

    The weak decay $B_c$ to $Z(3930)$ and $X(4160)$ by Bethe-Salpeter method

    Zhi-Hui Wang🇨🇳 · Yi Zhang🇨🇳 · Tian-hong Wang🇨🇳 · Yue Jiang🇨🇳 · Guo-Li Wang🇨🇳

    Considering $Z(3930)$ and $X(4160)$ as ${\chi }_{c2}(2P)$ and ${\chi }_{c2}(3P)$ states, the semileptonic and nonleptonic of $B_c$ decays to $Z(3930)$ and $X(4160)$ are studied by the improved Bethe-Salpeter(B-S) Method. The form factors of decay are calculated through the overlap integrals of the meson wave functions in the whole accessible kinematical range. The influence of relativistic corrections are considered in the exclusive decays. Branching ratios of $B_c$ weak decays to $Z(3930)$ and $X(4160)$ are predicted. Some of the branching ratios are: $Br(B_c^{+}\to Z(3930)e^{+}{\nu }_e)$$=(3.03_{-0.16}^{+0.09})\times 10^{-4}$ and $Br(B_c^{+}\to X(4160)e^{+}{\nu }_e)$$=(3.55_{-0.35}^{+0.83})\times 10^{-6}$. These results may provide useful information to discover $Z(3930)$ and $X(4160)$ and the necessary information for the phenomenological study of $B_c$ physics.

    hep-phEPJC(2020)·1 citation
22. 22*

    Hadronization of heavy diquark and light quark within NJL-Model

    Yu-Ji Shi🇩🇪

    We present a path-integral hadronization for doubly heavy baryons. The two heavy quarks in the baryon are approximated as a scalar or axial-vector diquark described by a heavy diquark effective theory. The gluon dynamics are represented by a NJL-Model interaction for the heavy diquarks and light quarks, which leads to an effective action of the baryon fields after the quark and diquark fields are integrated out. This effective action for doubly heavy baryon includes the electromagnetic and electroweak interactions, as well as the interaction with light mesons. We also verify the Ward-Takahashi identity at the baryon level, obtain the Isgur-Wise function for weak transitions, and calculate the strong coupling constant of the doubly heavy baryon and pion. Numerical studies are also performed.

    hep-phnucl-th1 citation
23. 23*

    Sensitivity reach on anomalous Higgs couplings via triphoton production for the post-LHC circular high-energy hadron colliders

    H. Denizli🇹🇷 · A. Senol🇹🇷

    The potential of triphoton production to obtain limits on anomalous Higgs boson couplings at $H\gamma \gamma$ and $HZ\gamma$ vertices is studied in Standard Model Effective Field Theory (EFT) framework for the post-LHC circular high-energy hadron colliders: High Luminosity-LHC (HL-LHC), High Energy LHC (HE-LHC) and Low Energy FCC (LE-FCC) which are designed with standard configurations of 14 TeV/3 ab${}^{-1}$, 27 TeV/15 ab${}^{-1}$ and 37.5 TeV/15 ab${}^{-1}$. Madgraph in which the effective Lagrangian of the SM EFT is implemented using FeynRules and UFO framework is used to generate both background and signal events. These events are then passed through Pythia 8 for parton showering and Delphes to include realistic detector effects. After optimizing cuts on kinematics of three photons as well as the reconstructed invariant mass of the two leading photons, invariant mass of three leading photon is used to obtain constraints on the Wilson coefficients of dimension-six operators. We report the result of two dimensional scan of ${\bar{c}}_{\gamma }$ and ${\tilde{c}}_{\gamma }$ couplings at 95\% confidence level and compare with LHC results. Our obtained limits without systematic error on ${\bar{c}}_{\gamma }$ ( ${\tilde{c}}_{\gamma }$) are $[-3.15;1.41]\times 10^{-2}$ ($[-2.12;2.12]\times 10^{-2}$), $[-1.21;0.78]\times 10^{-2}$ ($[-0.98;0.98]\times 10^{-2}$) and $[-0.89;0.66]\times 10^{-2}$ ($[-0.77;0.77]\times 10^{-2}$) for HL-LHC, HE-LHC and LE-FCC, respectively.

    hep-phActa Phys.Polon.B(2021)·9 citations
24. 24*

    The X(3872) tetraquarks in B and B_s decays

    Luciano Maiani🇮🇹 · Antonio D. Polosa🇮🇹 · Veronica Riquer🇮🇹

    We discuss how the latest data on X(3872) in B and B_s decays speak about its tetraquark nature. The established decay pattern, including the up to date observations by CMS, are explained by the mixing of two quasi-degenerate, unresolvable, neutral states. The same mechanism also explains isospin violations in X decays and strongly suggests that the lurking charged partners are required to have very small branching fractions in J/psi rho^pm, well below the current experimental limits. In addition, a new prediction on the decay into J/psi omega final states is attained. The newest experimental observations are found to give thrust to the simplest tetraquark picture and call for a definitive, in-depth study of final states with charged rho mesons.

    hep-phPRD(2020)·27 citations
25. 25*

    Theory for quarkonium: from NRQCD factorization to soft gluon factorization

    An-Ping Chen🇨🇳 · Yan-Qing Ma🇨🇳

    We demonstrate that the recently proposed soft gluon factorization (SGF) is equivalent to the nonrelativistic QCD (NRQCD) factorization for heavy quarkonium production or decay, which means that for any given process these two factorization theories are either both valid or both violated. We use two methods to achieve this conclusion. In the first method, we apply the two factorization theories to the physical process $J/\psi \to e^{+}{e}^{-}$. Our explicit calculation shows that both SGF and NRQCD can correctly reproduce low energy physics of full QCD, and thus the two factorizations are equivalent. In the second method, by using equations of motion we successfully deduce SGF from NRQCD effective field theory. By identifying SGF with NRQCD factorization, we establish relations between the two factorization theories and prove the generalized Gremm-Kapustin relations as a by product. Comparing with the NRQCD factorization, the advantage of SGF is that it resums the series of relativistic corrections originated from kinematic effects to all powers, which gives rise to a better convergence in relativistic expansion.

    hep-phCPC(2021)·10 citations
26. 26*

    Prompt $J/\psi$ photoproduction within the non-relativistic QCD framework at the CEPC

    Xi-Jie Zhan🇨🇳 · Jian-Xiong Wang🇨🇳

    The prompt $J/\psi$ photoproduction within the non-relativistic QCD (NRQCD) framework at the future Circular Electron Positron Collider (CEPC) is studied, including the contributions from both direct and resolved photons. Employing different sets of long distance matrix elements, the total cross section is dominated by the color-octet channel. We present different kinematic distributions of $J/\psi$ production and the results show there will be about 50 $J/\psi$ events when the transverse momentum of $J/\psi$ is up to 20 GeV. It renders that the $J/\psi$ photoprodution at the CEPC is a well laboratory to test the NRQCD and further clarify the universality problem in NRQCD between electron positron collider and hadron collider.

    hep-phEPJC(2020)·5 citations
27. 27*

    Searching for low mass dark matter via phonon creation in superfluid 4He

    Gordon Baym🇺🇸 · D. H. Beck🇺🇸 · Jeffrey P. Filippini🇺🇸 · C. J. Pethick🇺🇸 · Jessie Shelton🇺🇸

    We consider the scattering of dark matter particles from superfluid liquid ${}^4$He, which has been proposed as a target for their direct detection. Focusing on dark matter masses below ~1 MeV, we demonstrate from sum-rule arguments the importance of the production of single phonons with energies $\omega \lesssim 1$ meV. We show further that the anomalous dispersion of phonons in liquid ${}^4$He at low pressures [i.e., $d^2\omega (q)/d{q}^2>0$, where $q$ and $\omega (q)$ are the phonon momentum and energy] has the important consequence that a single phonon will decay over a relatively short distance into a shower of lower energy phonons centered on the direction of the original phonon. Thus the experimental challenge in this regime is to detect a shower of low energy phonons, not just a single phonon. Additional information from the distribution of phonons in such a shower could enhance the determination of the dark matter mass.

    hep-phastro-ph.COcond-mat.othercond-mat.supr-conPRD(2020)·33 citations
28. 28*

    Dark sector origin of the KOTO and MiniBooNE anomalies

    Alakabha Datta🇺🇸 · Saeed Kamali🇺🇸 · Danny Marfatia🇺🇸

    We present a dark sector model that reproduces the KOTO, MiniBooNE and muon anomalous magnetic moment anomalies. The dark sector is comprised of a light scalar singlet $S$ that has a large coupling to a slightly heavier sterile neutrino that mixes with the active neutrinos. The scalar couples to standard model fermions via Yukawa couplings, and to photons via a higher-dimensional coupling. The KOTO signal is a result of the flavor-changing penguin process $K_L\to {\pi }^{0}S$ followed by the decay of $S$ to neutrinos. The sterile neutrino produced in neutrino-nucleus scattering at MiniBooNE decays to an active neutrino and $S$, which decays electromagnetically and creates an event excess at low energies.

    hep-phhep-exPLB(2020)·58 citations
29. 29*

    Polarization in low energy kaon-hyperon interaction

    Marcelo G. L. Nogueira-Santos🇧🇷 · Celso C. Barros Jr🇧🇷

    In this paper, we study the low energy kaon-hyperon interaction considering effective chiral Lagrangians that include kaons, $\sigma$ mesons, hyperons and the corresponding resonances. The scattering amplitudes are calculated and then we determine the angular distributions and polarizations.

    hep-phnucl-thIJMPE(2020)·7 citations
30. 30*

    Isospin-breaking in ${\epsilon }^{\prime }/\epsilon$: Impact of ${\eta }_0$ at the Dawn of the 2020s

    Andrzej J. Buras🇩🇪 · Jean-Marc Gerard🇧🇪

    For direct CP-violation in $K\to \pi \pi$ decays, the usual isospin-breaking effects at the percent level are amplified by the dynamics behind the $\Delta I=1/2$ rule and conventionally encoded in ${\Omega }_{\mathrm{IB}}$ parameters. The updated prediction ${\Omega }_{\mathrm{IB}}^{(8)}=(15.9\pm 8.2)\times 10^{-2}$ of the Chiral Perturbation Theory for the strong isospin-breaking due to ${\pi }_3-{\eta }_8$ mixing confirms such a tendency but is quite sensitive to the theoretical input value of the low-energy constant corresponding to the flavour-singlet ${\eta }_0$ exchange contribution in this truncated octet scheme. We rather exploit the phenomenological ${\eta }_8-{\eta }_0$ mixing as a probe for the non-negligible flavour-singlet component of the physical $\eta$ pole to find ${\Omega }_{\mathrm{IB}}^{(9)}=(35\pm 7)\times 10^{-2}$ in a complete nonet scheme. A large central value in the nonet scheme is thus substituted for a large uncertainty in the octet one. Including the experimental ${\pi }^{+}-{\pi }^0$ mass difference as the dominant electromagnetic isospin-breaking, we obtain for the effective parameter entering the ratio ${ϵ}^{\prime }/ϵ$ an improved result ${\hat{\Omega }}_{\mathrm{eff}}^{(9)}=(29\pm 7)\times 10^{-2}$ to be compared with ${\hat{\Omega }}_{\mathrm{eff}}^{(8)}=(17\pm 9)\times 10^{-2}$ used in recent analyses of ${ϵ}^{\prime }/ϵ$. Accordingly, we get a reduction from $({ϵ}^{\prime }/ϵ{)}_{\mathrm{SM}}^{(8)}=(17.4\pm 6.1)\times 10^{-4}$ to $({ϵ}^{\prime }/ϵ{)}_{\mathrm{SM}}^{(9)}=(13.9\pm 5.2)\times 10^{-4}$ and thereby an effective suppression of $({ϵ}^{\prime }/ϵ{)}_{\mathrm{SM}}$ by isospin-breaking corrections as large as $40\%$ relative to the recent RBC-UKQCD value.

    hep-phhep-exhep-latEPJC(2020)·17 citations
31. 31*

    Probing Energetic Light Dark Matter with Multi-Particle Tracks Signatures at DUNE

    Albert De Roeck🇨🇭 · Doojin Kim🇺🇸 · Zahra Gh. Moghaddam🇮🇹 · Jong-Chul Park🇰🇷 · Seodong Shin🇰🇷 · Leigh H. Whitehead🇬🇧

    The search for relativistic scattering signals of cosmogenic light dark matter at terrestrial detectors has received increasing attention as an alternative approach to probe dark-sector physics. Large-volume neutrino experiments are well motivated for searches of dark matter that interacts very weakly with Standard Model particles and/or that exhibits a small incoming flux. We perform a dedicated signal sensitivity study for a detector similar to the one proposed by the DUNE Collaboration for cosmogenic dark-matter signals resulting from a non-minimal multi-particle dark-sector scenario. The liquid argon time projection chamber technology adopted for the DUNE detectors is particularly suited for searching for complicated signatures owing to good measurement resolution and particle identification, as well as $dE/dx$ measurements to recognize merged tracks. Taking inelastic boosted dark matter as our benchmark scenario that allows for multiple visible particles in the final state, we demonstrate that the DUNE far detectors have a great potential for probing scattering signals induced by relativistic light dark matter. Detector effects and backgrounds have been estimated and taken into account. Model-dependent and model-independent expected sensitivity limits for a DUNE-like detector are presented.

    hep-phhep-exJHEP(2020)·29 citations
32. 32*

    Higgs Portal From The Atmosphere To Hyper-K

    Paul Archer-Smith🇨🇦 · Yue Zhang🇨🇦

    A light Higgs portal scalar could be abundantly produced in the earth's atmosphere and decay in large-volume neutrino detectors. We point out that the Hyper-Kamiokande detector bears a strong discovery potential of probing such particles in an uncharted parameter space that is actively explored by intensity frontier experiments including rare kaon decays. The signal we propose to look for is electron-positron pair creation that manifests as a double-ring appearing from the same vertex. Most of these pairs originate from zenith angles above the Hyper-K detector's horizon. This search can be generalized to other new light states and is highly complementary to beam experiments.

    hep-phhep-exPLB(2021)·12 citations
33. 33*

    Boosting Freeze-in through Thermalization

    Nicolás Bernal🇨🇴

    If the interaction rates between the visible and the dark sectors were never strong enough, the observed dark matter relic abundance could have been produced in the early Universe by non-thermal processes. This is what occurs in the so-called freeze-in mechanism. In the simplest version of the freeze-in paradigm, after dark matter is produced from the standard model thermal bath, its abundance is frozen and remains constant. However, thermalization and number-changing processes in the dark sector can have strong impacts, in particular enhancing the dark matter relic abundance by several orders of magnitude. Here we show that this enhancement can be computed from general arguments as the conservation of energy and entropy, independently from the underlying particle physics details of the dark sector. We also note that this result is quite general, and applies to FIMP production independently of being UV- or IR-dominated.

    hep-phJCAP(2020)·52 citations
34. 34*

    Exact Relations for Two-Photon-Exchange Effect in Elastic $ep$ Scattering by Dispersion Relation and Hadronic Model

    Hui-Yun Cao🇨🇳 · Hai-Qing Zhou🇨🇳

    The two-photon-exchange (TPE) effect plays a key role to extract the form factors (FFs) of the proton. In this work, we present some exact properties on the TPE effect in the elastic $ep$ scattering based on four types of typical and general interactions. The possible kinematical singularities, the asymptotic behaviors and the branch cuts of the TPE amplitudes are analyzed. The analytic expressions clearly indicate some exact relations between the dispersion relation (DR) method and the hadronic model (HM) method. It suggests that the two methods should be modified to general forms, respectively. After the modifications the new forms give the same results. Furthermore, they automatically and correctly include the contributions due to the seagull interaction, the meson-exchange effect, the contact interactions and the off-shell effect. To analyze the elastic $e^{\pm }p$ scattering data sets, the new forms should be used.

    ↳ nucl-thhep-exhep-phnucl-exCPC(2021)·5 citations
35. 35*

    Heavy flavors under extreme conditions in high energy nuclear collisions

    Jiaxing Zhao🇨🇳 · Kai Zhou🇩🇪 · Shile Chen🇨🇳 · Pengfei Zhuang🇨🇳

    Heavy flavor hadrons have long been considered as a probe of the quark gluon plasma created in high energy nuclear collisions. In this paper we review the heavy flavor properties under extreme conditions and the realization in heavy ion experiments. After a short introduction on heavy flavor properties in vacuum, we emphasize the cold and hot nuclear matter effects on heavy flavors, including shadowing effect, Cronin effect and nuclear absorption for the former and Debye screening and regeneration for the latter. Then we discuss, in the frame of transport and coalescence models, these medium induced changes in open and closed heavy flavors in nuclear collisions and the comparison with nucleon-nucleon collisions. Considering the extremely strong electromagnetic and rotational fields generated in non-central nuclear collisions, which are widely studied in recent years, we finally investigate their effects on heavy flavor production and evolution in high energy nuclear collisions.

    ↳ nucl-thhep-phPPNP(2020)·138 citations
36. 36*

    String Cosmology backgrounds from Classical String Geometry

    Heliudson Bernardo🇨🇦 · Robert Brandenberger🇨🇦 · Guilherme Franzmann🇸🇪

    We introduce a very early universe model based on the thermodynamics of a gas of closed strings in a background which is non-perturbative in ${\alpha }^{\prime }$. Upon considering the fully ${\alpha }^{\prime }$-corrected equations extended to include certain anisotropic cosmological backgrounds, we describe the evolution of the system in three different stages parametrized by the gas' equation of state. Using standard string thermodynamical arguments, we start with an isotropic 10-dimensional universe inside the string scale and evolve it towards a universe with four large spacetime dimensions and six stabilized internal dimensions in the Einstein frame.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2021)·40 citations
37. 37*

    Chiral random matrix theory for colorful quark-antiquark condensates

    Takuya Kanazawa🇯🇵

    In QCD at high density, the color-octet quark-antiquark condensate $⟨\overline{\psi }{\gamma }_0({\lambda }^A{)}_C({\lambda }^A{)}_F\psi ⟩$ is generally nonzero and dynamically breaks the $\mathrm{SU}(3{)}_C\times \mathrm{SU}(3{)}_L\times \mathrm{SU}(3{)}_R$ symmetry down to the diagonal $\mathrm{SU}(3{)}_V$. We evaluate this condensate in the mean-field approximation and find that it is of order $\mu {\Delta }^2\log (\mu /\Delta )$ where $\Delta$ is the BCS gap of quarks. Next we propose a novel non-Hermitian chiral random matrix theory that describes the formation of colorful quark-antiquark condensates. We take the microscopic large-$N$ limit and find that three phases appear depending on the parameter of the model. They are the color-flavor locked phase, the polar phase, and the normal phase. We rigorously derive the effective theory of Nambu-Goldstone modes and determine the quark-mass dependence of the partition function.

    ↳ hep-thhep-lathep-phmath-ph+1PRD(2020)·2 citations
38. 38*

    Charmonium transition in electromagnetic and rotational fields

    Shile Chen🇨🇳 · Jiaxing Zhao🇨🇳 · Pengfei Zhuang🇨🇳

    We study charmonia in electromagnetic and rotational fields in the frame of a potential model. Different from the temperature field which is isotropic and leads to the well-known charmonium dissociation, the electromagnetic and rotational fields break down the radial symmetry, and the competition between strong interaction and electromagnetic and rotational interaction in the direction of Lorentz force makes the charmonia transit from an isotropic bound state of strong interaction with positive binding energy to an anisotropic bound state of electromagnetic and rotational interaction with negative binding energy. The transition seems possible to be realized in high energy nuclear collisions.

    ↳ nucl-thhep-phPRC(2021)·21 citations
39. 39*

    Precision measurement of ${}^{210}$Bi $\beta$-spectrum

    I.E. Alekseev🇷🇺 · S.V. Bakhlanov🇷🇺 · A.V. Derbin🇷🇺 · I.S. Drachnev🇷🇺 · I.M. Kotina🇷🇺 · I.S. Lomskaya🇷🇺 · V.N. Muratova🇷🇺 · N.V. Niyazova🇷🇺 · D.A. Semenov🇷🇺 · M.V. Trushin🇷🇺 · E.V. Unzhakov🇷🇺

    The precision measurement of the $\beta -$spectrum shape for ${}^{210}$Bi (historically RaE) have been performed with a spectrometer based on semiconductor Si(Li) detector. This first forbidden non-unique transition has the transition form-factor strongly deviated from unity and knowledge of its spectrum would play an important role in low-background physics in presence of ${}^{210}$Pb background. The measured transition form-factor could be approximated as $S(W)=1+(-0.4363\pm 0.0037)W+(0.0523\pm 0.0010)W^2$, that is in good agreement with previous studies and has significantly increased parameter precision.

    ↳ nucl-exhep-exhep-phnucl-th+1PRC(2021)·12 citations
40. 40*

    Quantum Machine Learning in High Energy Physics

    Wen Guan🇺🇸 · Gabriel Perdue🇺🇸 · Arthur Pesah🇩🇰 · Maria Schuld🇿🇦 · Koji Terashi🇯🇵 · Sofia Vallecorsa🇨🇭 · Jean-Roch Vlimant🇺🇸

    Machine learning has been used in high energy physics for a long time, primarily at the analysis level with supervised classification. Quantum computing was postulated in the early 1980s as way to perform computations that would not be tractable with a classical computer. With the advent of noisy intermediate-scale quantum computing devices, more quantum algorithms are being developed with the aim at exploiting the capacity of the hardware for machine learning applications. An interesting question is whether there are ways to apply quantum machine learning to High Energy Physics. This paper reviews the first generation of ideas that use quantum machine learning on problems in high energy physics and provide an outlook on future applications.

    ↳ quant-phhep-phMach.Learn.Sci.Tech.(2021)·140 citations
41. 41*

    Dark photon dark matter and fast radio bursts

    Ricardo G. Landim🇩🇪

    The nature of dark matter (DM) is still a mystery that may indicate the necessity for extensions of the Standard Model (SM). Light dark photons (DP) may comprise partially or entirely the observed DM density and existing limits on the DP DM parameter space arise from several cosmological and astrophysical sources. In the present work we investigate DP DM using cosmic transients, specifically fast radio bursts (FRBs). The observed time delay of radio photons with different energies have been used to constrain the photon mass or the Weak Equivalence Principle, for example. Due to the mixing between the visible and the DP, the time delay of photons from these cosmic transients, caused by free electrons in the intergalactic medium, can change and impact those constraints from FRBs. We use five detected FRBs and two associations of FRBs with gamma-ray bursts to investigate the correspondent variation on the time delay caused by the presence of DP DM. The result is virtually independent of the FRB used and this variation is very small, considering the still allowed DP DM parameter space, not jeopardizing current bounds on other contributions of the observed time delay.

    ↳ astro-ph.COastro-ph.HEhep-phEPJC(2020)·11 citations
42. 42*

    Observational Constraints on Axion(s) Dark Energy with a Cosmological Constant

    Ruchika🇮🇳 · Shahnawaz A. Adil🇮🇳 · Koushik Dutta🇮🇳 · Ankan Mukherjee🇮🇳 · Anjan A. Sen🇮🇳

    The present work deals with a dark energy model that has an oscillating scalar field potential along with a cosmological constant (CC). The oscillating part of the potential represents the contribution of a light axion field in the dark energy that has its origin in the String-Axiverse scenario. The model has been confronted with the latest cosmological observations. The results show that a sub-Planckian value of the axion field decay constant is consistent with observational data. Furthermore, in terms of the observational data considered in this work, the axion model is preferred over the $\Lambda$CDM model in terms of AIC, BIC information criteria as well as in terms of Bayesian evidence. The oscillating feature in the scalar field evolution and in the equation of state for the dark energy can be observed for the allowed parameters space. It is also observed that cluster number counts in this axion model are suppressed compared to the $\Lambda$CDM and this suppression is enhanced for the sub-Planckian values for the axion decay constant.

    ↳ astro-ph.COhep-phhep-thPhys.Dark Univ.(2023)·43 citations
43. 43*

    High-Energy Neutrino and Gamma-Ray Emission from Tidal Disruption Events

    Kohta Murase🇺🇸 · Shigeo S. Kimura🇯🇵 · B. Theodore Zhang🇺🇸 · Foteini Oikonomou🇳🇴 · Maria Petropoulou🇺🇸

    Tidal disruption events (TDE) have been considered as cosmic-ray and neutrino sources for a decade. We suggest two classes of new scenarios for high-energy multi-messenger emission from TDEs that do not have to harbor powerful jets. First, we investigate high-energy neutrino and gamma-ray production in the core region of a supermassive black hole. In particular, we show that about 1-100 TeV neutrinos and MeV gamma-rays can efficiently be produced in hot coronae around an accretion disk. We also study the consequences of particle acceleration in radiatively inefficient accretion flows (RIAFs). Second, we consider possible cosmic-ray acceleration by sub-relativistic disk-driven winds or interactions between tidal streams, and show that subsequent hadronuclear and photohadronic interactions inside the TDE debris lead to GeV-PeV neutrinos and sub-GeV cascade gamma-rays. We demonstrate that these models should be accompanied by soft gamma-rays or hard X-rays as well as optical/UV emission, which can be used for future observational tests. Although this work aims to present models of non-jetted high-energy emission, we discuss the implications of the TDE AT2019dsg that might coincide with the high-energy neutrino IceCube-191001A, by considering the corona, RIAF, hidden sub-relativistic wind, and hidden jet models. It is not yet possible to be conclusive about their physical association and the expected number of neutrinos is typically much less than unity. We find that the most optimistic cases of the corona and hidden wind models could be consistent with the observation of IceCube-191001A, whereas jet models are unlikely to explain the multi-messenger observations.

    ↳ astro-ph.HEhep-phApJ(2020)·120 citations
44. 44*

    Soft Matters, or the Recursions with Massive Spinors

    Adam Falkowski🇫🇷 · Camila S. Machado🇩🇪

    We discuss recursion relations for scattering amplitudes with massive particles of any spin. They are derived via a two-parameter shift of momenta, combining a BCFW-type spinor shift with the soft limit of a massless particle involved in the process. The technical innovation is that spinors corresponding to massive momenta are also shifted. Our recursions lead to a reformulation of the soft theorems. The well-known Weinberg's soft factors are recovered and, in addition, the subleading factors appear reshaped such that they are directly applicable to massive amplitudes in the modern on-shell language. Moreover, we obtain new results in the context of non-minimal interactions of massive matter with photons and gravitons. These soft theorems are employed for practical calculations of Compton and higher-point scattering. As a by-product, we introduce a convenient representation of the Compton scattering amplitude for any mass and spin.

    ↳ hep-thhep-phJHEP(2021)·56 citations
45. 45*

    Millisecond Pulsars Modify the Radio-SFR Correlation in Quiescent Galaxies

    Takahiro Sudoh🇯🇵 · Tim Linden🇸🇪 · John F. Beacom🇺🇸

    The observed correlation between the far-infrared and radio luminosities of galaxies illustrates the close connection between star formation and cosmic-ray production. Intriguingly, recent gamma-ray observations indicate that recycled/millisecond pulsars (MSPs), which do not trace recent star formation, may also efficiently accelerate cosmic-ray electrons. We study the contribution of MSPs to the galactic non-thermal radio emission, finding that they can dominate the emission from massive quiescent galaxies. This model can explain recent LOFAR observations that found a peculiar radio excess in galaxies with high stellar masses and low star-formation rates. We show that MSP-based models provide a significantly improved fit to LOFAR data. We discuss the implications for the radio-FIR correlation, the observation of radio excesses in nearby galaxies, and local electron and positron observations.

    ↳ astro-ph.GAastro-ph.HEhep-phPRD(2021)·18 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.