Tue·Jan 12, 2021Tuesday·January 12, 2021

1. 01*

   Spectroscopy of the tetraquark $c\bar{c}$-$c\bar{c}$ in a non-relativistic approach using a phenomenological QCD model

   J. A. Lesteiro-Tejeda🇨🇺 · D. A. Ramírez-Zaldívar🇨🇺 · C. E. Gracía-Trápaga🇨🇺 · F. Guzmán-Martínez🇨🇺

   Hadron spectroscopy is a powerful tool for testing the standard model and for the search of new physics. In this work, we create a tetraquark model from a di-meson interaction inspired by Jacobi coordinates. We consider mesons as thick points and quantify their interaction with the quark-antiquark interaction through a factor k (that takes approximately the value 2) in a central phenomenological potential, reducing the four-body problem finally to a one body equivalent problem. The eigenproblem is solved using a combination of the DVR method and perturbation theory in a C++ code. We obtain a mass spectrum for the tetraquark between 6 GeV and 8 GeV for the ground and first energy excitation level. Our calculation indicates that our system is compact and that the non-relativistic approach used in all our formalism is valid.

   hep-ph5 citations
2. 02*

   Phenomenology of $J^{PC}=3^{--}$ tensor mesons

   Shahriyar Jafarzade🇵🇱 · Adrian Koenigstein🇩🇪 · Francesco Giacosa🇵🇱

   We study the strong and radiative decays of the anti-quark-quark ground state $J^{PC}=3^{--}$ ($n^{2S+1}{L}_J=1^3{D}_3$) nonet {${\rho }_3(1690)$, $K_3^{\ast }(1780)$, ${\varphi }_3(1850)$, ${\omega }_3(1670)$} in the framework of an effective quantum field theory approach, based on the $S{U}_{\mathrm{V}}(3)$-flavor-symmetry. The effective model is fitted to experimental data listed by the Particle Data Group. We predict numerous experimentally unknown decay widths and branching ratios. An overall agreement of theory (fit and predictions) with experimental data confirms the $\bar{q}q$ nature of the states and qualitatively validates the effective approach. Naturally, experimental clarification as well as advanced theoretical description is needed for trustworthy quantitative predictions, which is observed from some of the decay channels. Besides conventional spin-$3$ mesons, theoretical predictions for ratios of strong and radiative decays of a hypothetical glueball state $G_3(4200)$ with $J^{PC}=3^{--}$ are also presented.

   hep-phPRD(2021)·22 citations
3. 03*

   Studies on the $K^{\ast }\Sigma$ bound-state via $K^{+}p\to K^{+}\varphi p$

   Seung-il Nam🇰🇷

   In the present work, we investigate the hidden-strangeness production process in the $S=+1$ channel via $K^{+}p\to K^{+}\varphi p$, focussing on the exotic \textit{pentaquark} molecular $K^{\ast }\Sigma$ bound state, assigned by $P_s^{+}(2071,3/2^{-})$. For this purpose, we employ the effective Lagrangian approach in the tree-level Born approximation. Using the experimental and theoretical inputs for the exotic state and for the ground-state hadron interactions, the numerical results show a small but obvious peak structure from $P_s^{+}$ with the signal-to-background ratio $\approx 1.7\%$, and it is enhanced in the backward-scattering region of the outgoing $K^{+}$ in the center-of-mass frame. We also find that the contribution from the $K^{\ast }(1680,1^{-})$ meson plays an important role to reproduce the data. The proton-spin polarizations are taken into account to find a way to reduce the background. The effects of the possible $27$-plet pentaquark ${\Theta }_{27}^{++}$ is discussed as well.

   hep-phhep-exnucl-thPRD(2021)·7 citations
4. 04*

   Fermion masses and mixings in a $U(1{)}_X$ model based on the $\Sigma (18)$ discrete symmetry

   V. V. Vien🇻🇳 · A. E. Cárcamo Hernández🇨🇱 · H. N. Long🇻🇳

   We have built a renormalizable $U(1{)}_X$ model with a $\Sigma (18)\times Z_4$ symmetry, whose spontaneous breaking yields the observed SM fermion masses and fermionic mixing parameters. The tiny masses of the light active neutrinos are produced by the type I seesaw mechanism mediated by very heavy right handed Majorana neutrinos. To the best of our knowledge, this model is the first implementation of the $\Sigma (18)$ flavor symmetry in a renormalizable $U(1{)}_X$ model. Our model allows a successful fit for the SM fermion masses, fermionic mixing angles and CP phases for both quark and lepton sectors. The obtained values for the physical observables of both quark and lepton sectors are in accordance with the experimental data. We obtain an effective neutrino mass parameter of $⟨m_{ee}⟩=1.51\times 10^{-3}\mathrm{eV}$ for normal ordering and $⟨m_{ee}⟩=4.88\times 10^{-2}\mathrm{eV}$ for inverted ordering which are well consistent with the recent experimental limits on neutrinoless double beta decay.

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

   New CP Phase and Exact Oscillation Probabilities of Dirac Neutrino derived from Relativistic Equation

   Keiichi Kimura🇯🇵 · Akira Takamura🇯🇵

   We present a new formulation for deriving neutrino oscillation probabilities relativistically, based not on the Schrödinger equation but on the Dirac equation. In the context of two generations, we calculate the oscillation probabilities precisely in a scenario where only the Dirac mass term is present. Our analysis reveals the emergence of two new features in the oscillation probabilities derived from the Dirac equation. The first feature is that the oscillation probabilities depend on the absolute value of the neutrino mass. While it has generally been assumed that oscillation probabilities depend solely on mass squared differences, we show that they also depend on the absolute mass. The second feature is the emergence of a new CP phase. If interactions exist that can distinguish the flavors of right-handed neutrinos in physics beyond the Standard Model, we could potentially observe this new CP phase even in the two-generation model. We discuss the feasibility of detecting the contributions of these features through neutrino oscillations at atomic scales. In contrast, these effects are negligible in conventional short- and long-baseline experiments, and no contradictions arise with previous findings.

   hep-phAnnals Phys.(2025)·10 citations
6. 06*

   Hybrid nature of the abnormal solutions of the Bethe-Salpeter equation in the Wick-Cutkosky model

   J. Carbonell · V.A. Karmanov ans H. Sazdjian

   In the Wick-Cutkosky model, where two scalar massive constituents interact by means of the exchange of a scalar massless particle, the Bethe-Salpeter equation has solutions of two types, called "normal" and "abnormal". In the non-relativistic limit, the normal solutions correspond to the usual Coulomb spectrum, whereas the abnormal ones do not have non-relativistic counterparts -- they are absent in the Schrödinger equation framework. We have studied, in the formalism of the light-front dynamics, the Fock-space content of the abnormal solutions. It turns out that, in contrast to the normal ones, the abnormal states are dominated by the massless exchange particles (by 90 \% or more), what provides a natural explanation of their decoupling from the two-body Schrödinger equation. Assuming that one of the massive constituents is charged, we have calculated the electromagnetic elastic form factors of the normal and abnormal states, as well as the transition form factors. The results on form factors confirm the many-body nature of the abnormal states, as found from the Fock-space analysis. The abnormal solutions have thus properties similar to those of hybrid states, made here essentially of two massive constituents and several or many massless exchange particles. They could also be interpreted as the Abelian scalar analogs of the QCD hybrid states. The question of the validity of the ladder approximation of the model is also examined.

   hep-phnucl-thEPJC(2021)·6 citations
7. 07*

   Twisted particles in heavy-ion collisions

   Alexander J. Silenko🇷🇺 · Pengming Zhang🇨🇳 · Liping Zou🇨🇳

   The importance of production of twisted (vortex) particles in heavy-ion collisions is analyzed. Free twisted particles can possess giant intrinsic orbital angular momenta. Twisted particles are spatially localized and can be rather ubiquitous in laboratories and nature. Twisted photons have nonzero effective masses. Charged twisted particles can be recognized by their dynamics, magnetic moments, and specific effects in external fields.

   hep-phhep-exhep-thPoS(2021)·0 citations
8. 08*

   Light-front dynamic analysis of the longitudinal charge density using the solvable scalar field model in (1+1) dimensions

   Yongwoo Choi🇰🇷 · Ho-Meoyng Choi🇰🇷 · Chueng-Ryong Ji🇺🇸 · Yongseok Oh🇰🇷

   We investigate the electromagnetic form factor $F(q^2)$ of the meson by using the solvable ${\varphi }^3$ scalar field model in $(1+1)$ dimensions. As the transverse rotations are absent in $(1+1)$ dimensions, the advantage of the light-front dynamics (LFD) with the light-front time $x^{+}=x^0+x^3$ as the evolution parameter is maximized in contrast to the usual instant form dynamics (IFD) with the ordinary time $x^0$ as the evolution parameter. In LFD, the individual $x^{+}$-ordered amplitudes contributing to $F(q^2)$ are invariant under the boost, i.e., frame-independent, while the individual $x^0$-ordered amplitudes in IFD are not invariant under the boost but dependent on the reference frame. The LFD allows to get the analytic result for the one-loop triangle diagram which covers not only the spacelike ($q^2<0$) but also timelike region ($q^2>0$). Using the analytic results, we verify that the real and imaginary parts of the form factor satisfy the dispersion relations in the entire $q^2$ space. Comparing with the results in $(3+1)$ dimensions, we discuss the transverse momentum effects on $F(q^2)$ . We also discuss the longitudinal charge density in terms of the boost invariant variable $\tilde{z}=p^{+}{x}^{-}$ in LFD.

   hep-phnucl-thPRD(2021)·5 citations
9. 09*

   The medium modification of high-virtuality partons

   Shanshan Cao🇺🇸 · Chathuranga Sirimanna🇺🇸 · Abhijit Majumder🇺🇸

   The modification of the hard core of jets in a dense QCD medium is studied. In particular, we consider partons which possess a virtuality somewhat larger than the multiple scattering scale of the medium ($\hat{q}\tau$, where $\hat{q}$ is the transverse broadening jet transport coefficient, and $\tau$ is the formation length of a particular emission). We delineate the region of parameter space where the higher-twist approach is applicable, and derive the in-medium DGLAP evolution equation. We study a region in parameter space where this is the dominant mechanism of energy loss. We argue that such a regime is pervasive in most cases of jets in $A$-$A$ and future $e$-$A$ collisions, and controls the modification of the hard core of jets and the leading single particle spectrum at high transverse momentum ($p_{\mathrm{T}}$).

   hep-ph13 citations
10. 10*

    Dark Photon As an Extra U(1) Extension to the Standard Model With general Rotation in Kinetic Mixing

    A.Berkane🇩🇿 · M. Boussahel🇩🇿

    An extension to the original dark photon model is proposed, by a generalization of matrix transformation with any angle {\theta} of orthogonal rotation. Not only all the results presented by the dark photon model have been accurately reproduced, but new horizons have been opened by exploring new fields induced by this generalization, with new possibilities in the investigation and research of dark photon in particular and dark matter in general.

    hep-ph0 citations
11. 11*

    Testing aligned CP-violating Higgs sector at future lepton colliders

    Shinya Kanemura🇯🇵 · Mitsunori Kubota🇯🇵 · Kei Yagyu🇯🇵

    We discuss the testability of CP-violating phases at future lepton colliders for the scenario which satisfies electric dipole moment data by destructive interferences among several phases. We consider the general but aligned two Higgs doublet model which has the CP-violating phases in the Higgs potential and the Yukawa interaction. The Yukawa interaction terms are aligned to avoid flavor changing neutral currents at tree level. The Higgs potential is also aligned such that the coupling constants of the lightest Higgs boson with the mass of 125 GeV to the Standard Model (SM) particles are the same as those of the SM at tree level. We investigate the azimuthal angle distribution of the hadronic decay of tau leptons arising from production and decay of the extra Higgs bosons, which contains information of the CP-violating phases. From the signal and background simulation, we find that the scenario with finite CP-violating phases can be distinguished from CP conserving one at future lepton colliders like the International Linear Collider.

    hep-phJHEP(2021)·17 citations
12. 12*

    Hot spots and gluon field fluctuations as causes of eccentricity in small systems

    S. Demirci🇫🇮 · T. Lappi🇫🇮 · S. Schlichting🇩🇪

    We calculate eccentricities in high energy proton-nucleus collisions, by calculating correlation functions of the energy density field of the Glasma immediately after the collision event at proper time tau = 0. We separately consider the effects of color charge and geometrical hot spot fluctuations, analytically performing the averages over both in a dilute-dense limit. We show that geometric fluctuations of hot spots inside the proton are the dominant source of eccentricity whereas color charge fluctuations only give a negligible correction. The size and number of hot spots are the most important parameters characterizing the eccentricities.

    hep-phnucl-thPRD(2021)·24 citations
13. 13*

    Dark Confinement-Deconfinement Phase Transition: A Roadmap from Polyakov Loop Models to Gravitational Waves

    Zhaofeng Kang🇨🇳 · Shinya Matsuzaki🇨🇳 · Jiang Zhu🇨🇳

    We explore the confinement-deconfinement phase transition (PT) of the first order (FO) arising in $SU(N)$ pure Yang-Mills theory, based on Polyakov loop models (PLMs), in light of the induced gravitational wave (GW) spectra. We demonstrate that the PLMs with the Haar measure term, involving models successful in QCD with $N=3$, are potentially incompatible with the large $N$ scaling for the thermodynamical quantities and the latent heat at around the criticality of the FOPT reported from the lattice simulations. We then propose a couple of models of polynomial form, which we call the 4-6 PLM (with four- and six-point interactions among the basic PL fields which have center charge 1) and 4-8 PLM (with four- and eight-point interactions), and discuss how such models can naturally arise in the presence of a heavy PL with charge 2. We show that those models give the consistent thermodynamical and large $N$ properties at around the criticality. The predicted GW spectra are shown to have high enough sensitivity to be probed in the future prospected interferometers such as LISA, BBO, DICIGO, and TianQin.

    hep-phhep-thJHEP(2021)·51 citations
14. 14*

    Fully-heavy tetraquark production by $\gamma \gamma$ interactions in hadronic collisions at the LHC

    Victor P. Goncalves🇧🇷 · Bruno D. Moreira🇧🇷

    We investigate the production of the fully - heavy tetraquark states $T_{4Q}$ in the $\gamma \gamma$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC). We focus on the $\gamma \gamma \to \mathcal{Q}\mathcal{Q}$ ($\mathcal{Q}=J/\psi ,{\rm Y}$) subprocess, mediated by the $T_{4Q}$ resonance in the $s$ - channel, and present predictions for the hadronic cross sections considering the kinematical ranges probed by the ALICE and LHCb Collaborations. Our results demonstrate that the experimental study of this process is feasible and can be used to investigate the existence and properties of the $T_{4c}(6900)$ and $T_{4b}(19000)$ states.

    hep-phhep-exPLB(2021)·49 citations
15. 15*

    Phenomenological assessment of proton mechanical properties from deeply virtual Compton scattering

    H. Dutrieux🇫🇷 · C. Lorcé🇫🇷 · H. Moutarde🇫🇷 · P. Sznajder🇵🇱 · A. Trawiński🇫🇷 · J. Wagner🇵🇱

    A unique feature of generalised parton distributions is their relation to the QCD energy-momentum tensor. In particular, they provide access to the mechanical properties of the proton i.e. the distributions of pressure and shear stress induced by its quark and gluon structure. In principle the pressure distribution can be experimentally determined in a model-independent way from a dispersive analysis of deeply virtual Compton scattering data through the measurement of the subtraction constant. In practice the kinematic coverage and accuracy of existing experimental data make this endeavour a challenge. Elaborating on recent global fits of deeply virtual Compton scattering measurements using artificial neural networks, our analysis presents the current knowledge on this subtraction constant and assesses the impact of the most frequent systematic assumptions made in this field of research. This study will pave the way for future works when more precise data will become available, e.g. obtained in the foreseen electron-ion colliders EIC and EIcC.

    hep-phEPJC(2021)·72 citations
16. 16*

    Remarks on Static Three-Quark Potentials, String Breaking and Gauge/String Duality

    Oleg Andreev🇷🇺

    Making use of the gauge/string duality, it is possible to study some aspects of the string breaking phenomenon in the three quark system. Our results point out that the string breaking distance is not universal and depends on quark geometry. The estimates of the ratio of the string breaking distance in the three quark system to that in the quark-antiquark system would range approximately from $\frac{2}{3}$ to $1$. In addition, it is shown that there are special geometries which allow more than one breaking distance.

    hep-phhep-lathep-thnucl-thPRD(2021)·22 citations
17. 17*

    Reweighting the Sivers function with jet data from STAR

    Mariaelena Boglione🇮🇹 · Umberto D'Alesio🇮🇹 · Carlo Flore🇫🇷 · Josè Osvaldo Gonzalez-Hernandez🇮🇹 · Francesco Murgia🇮🇹 · Alexei Prokudin🇺🇸

    The reweighting procedure that using Bayesian statistics incorporates the information contained in a new data set, without the need of re-fitting, is applied to the quark Sivers function extracted from Semi-Inclusive Deep Inelastic Scattering (SIDIS) data. We exploit the recently published single spin asymmetry data for the inclusive jet production in polarized $pp$ collisions from the STAR Collaboration at RHIC, which cover a much wider $x$ region compared to SIDIS measurements. The reweighting method is extended to the case of asymmetric errors and the results show a remarkable improvement of the knowledge of the quark Sivers function.

    hep-phhep-exPLB(2021)·15 citations
18. 18*

    Linear energy density and the flux of an electric field in Proca tubes

    Vladimir Dzhunushaliev🇰🇿 · Vladimir Folomeev🇰🇿 · Abylaikhan Tlemisov🇰🇿

    We study cylindrically symmetric solutions within SU(3) non-Abelian Proca theory coupled to a Higgs scalar field. The solutions describe tubes containing either the flux of a color electric field or the energy flux and momentum. It is shown that the existence of such tubes depends crucially on the presence of the Higgs field (there are no such solutions without this field). We examine the dependence of the integral characteristics (linear energy and momentum densities) on the values of the electromagnetic potentials at the center of the tube, as well as on the values of the coupling constant of the Higgs scalar field. The solutions obtained are topologically trivial and they demonstrate the dual Meissner effect: the electric field is pushed out by the Higgs scalar field.

    hep-phhep-thSymmetry(2021)·4 citations
19. 19*

    Multi-Higgs Production Probes Higgs Flavor

    Daniel Egana-Ugrinovic🇨🇦 · Samuel Homiller🇺🇸 · Patrick Meade🇺🇸

    We demonstrate that multiple-Higgs production at the LHC is the most sensitive probe of first and second-generation quark flavor in the Higgs sector. In models where new scalars couple to light quarks, gigantic di-Higgs and even sizable tri-Higgs production rates can be obtained, which can be used to either discover or severely constrain such theories. As an example, we show that the most stringent bounds on enhanced interactions of the $125\text{GeV}$ Higgs to the down quark in extended Higgs sectors are obtained by looking for the extra Higgs bosons that provide for such enhancements using the di-Higgs and $Zh$ topologies. In this context, we set new limits on the 125 GeV Higgs coupling to the down quark as strong as ${\lambda }_{hd\bar{d}}\lesssim 30{\lambda }_{hd\bar{d}}^{\text{SM}}$ -- a dramatic improvement over previously available bounds. Regarding second-generation quark flavor, we obtain new limits in the coupling to strange as strong as ${\lambda }_{hs\bar{s}}\lesssim 10{\lambda }_{hs\bar{s}}^{\text{SM}}$. In addition, we show that the currently unexplored triple-Higgs production topology could be a potential discovery channel of a wide variety of extended Higgs sectors at the LHC, including not only models where extra Higgses couple to light quarks, but also popular theories where they have preferential couplings to the the top.

    hep-phhep-exPRD(2021)·26 citations
20. 20*

    Physics with Leptons and Photons at the LHC

    L. A. Harland-Lang🇬🇧

    We present a phenomenological study of photon-initiated (PI) lepton production at the LHC, as implemented in the structure function (SF) approach. We provide detailed predictions for multi-differential lepton pair production, and show that the impact on observables sensitive to the the weak mixing angle, ${\sin }^2{\theta }_W$, and $W$ boson mass, $M_W$, as well as PDFs can be non-negligible, in particular given the high precision being aimed for. The SF calculation can provide percent level precision in the corresponding production cross sections, and is therefore well positioned to account for LHC precision requirements. We consider the pure $\gamma \gamma$ channel, and compare in detail to the NLO collinear calculation. We in addition include initial-state $Z$ as well as mixed $\gamma /Z+q$ contributions, and assess their impact. We also consider photon-initiated lepton-lepton scattering, and again find the SF approach can provide high precision predictions for this process in way that can straightforwardly account for any fiducial cuts imposed. Finally, we provide a publicly available Monte Carlo generator, SFGen, for PI lepton pair production and lepton-lepton scattering within the SF approach, for use by the community.

    hep-phhep-exPRD(2021)·21 citations
21. 21*

    Glueballs as the Ithaca of meson spectroscopy

    Felipe J. Llanes-Estrada (Univ. Complutense de Madrid)🇪🇸

    This compact review about gluonium focuses on a slate of theoretical efforts; among the many standing works, I have selected several that are meant to assist in the identification, among ordinary mesons, of the few Yang-Mills glueball configurations that populate the energy region below 3 GeV. This includes $J/\psi$ radiative and vector-meson decays, studies of scalar meson mixing, of high-energy cross sections via the Pomeron and the odderon, glueball decays, etc. The weight of accumulated evidence seems to support the $f_0(1710)$ as having a large (and the largest) glueball component among the scalars, although no single observable by itself is conclusive. Further tests would be welcome, such as exclusive $f_J$ production at asymptotically high $s$ and $t$. No clear experimental candidates for the pseudoscalar or tensor glueball stand out yet, and continuing investigations trying to sort them out will certainly teach us much more about mesons.

    hep-phEur.Phys.J.ST(2021)·42 citations
22. 22*

    Elastic dcs of ep-scattering fitted via the dcs of eq-scatterings with cloud-covering effects

    Jingle B. Magallanes🇵🇭 · Jinky B. Bornales🇵🇭 · René Luna-García🇲🇽

    The angular-averaged differential cross section (dcs) of the elastic electron proton (ep) scattering, covering Q^2 < 1.0GeV^2, was fitted via a combined modified eq-scatterings where q is a point particle. The modifications represent the cloud-covering effects to q. An energy-decaying ratio (edr) was derived by inspecting the generated dcs ep from the form factor data gathered at Mainz Microtron (A1-Collaboration) and Continuous Electron Beam Accelerator Facility (Jefferson Laboratory) when compared to the dcs eq with modified relativistic recoil factor. The diminishing cloud layer, edr, has a decay rate of -2.8 for the data sets under investigation. The formulated SBM and SEM fitting models use the bare and effective u and d-quark masses, respectively, while SCBM and SCEM integrate other considerations. Three comparison methods were used and all of them favor the models with other additional considerations. SCEM was the most favored model in general.

    hep-phPRD(2021)·0 citations
23. 23*

    Satisfiability Modulo Theories and Chiral Heterotic String Vacua with Positive Cosmological Constant

    Alon E. Faraggi🇬🇧 · Benjamin Percival🇬🇧 · Sven Schewe🇬🇧 · Dominik Wojtczak🇬🇧

    We apply Boolean Satisfiability (SAT) and Satisfiability Modulo Theories (SMT) solvers in the context of finding chiral heterotic string models with positive cosmological constant from ${\mathbb{Z}}_2\times {\mathbb{Z}}_2$ orbifolds. The power of using SAT/SMT solvers to sift large parameter spaces quickly to decide satisfiability, both to declare and prove unsatisfiability and to declare satisfiability, are demonstrated in this setting. These models are partly chosen to be small enough to plot the performance against exhaustive search, which takes around 2 hours 20 minutes to comb through the parameter space. We show that making use of SMT based techniques with integer encoding is rather simple and effective, while a more careful Boolean SAT encoding provides a significant speed-up -- determining satisfiability or unsatisfiability has, in our experiments varied between 0.03 and 0.06 seconds, while determining all models (where models exist) took 19 seconds for a constraint system that allows for 2048 models and 8.4 seconds for a constraint system that admits 640 models. We thus gain several orders of magnitude in speed, and this advantage is set to grow with a growing parameter space. This holds the promise that the method scales well beyond the initial problem we have used it for in this paper.

    ↳ hep-thhep-phPLB(2021)·21 citations
24. 24*

    Response of undoped cryogenic CsI to low-energy nuclear recoils

    C.M. Lewis🇺🇸 · J.I. Collar🇺🇸

    The bright scintillation of pure CsI operated at liquid-nitrogen temperature makes of this material a promising dark matter and neutrino detector. We present the first measurement of its quenching factor for nuclear recoils. Our findings indicate it is indistinguishable from that for sodium-doped CsI at room temperature. Additional properties such as light yield, afterglow, scintillation decay properties for electron and nuclear recoils, and energy proportionality are studied over the \mbox{108-165 K} temperature range, confirming the vast potential of this medium for rare-event searches.

    ↳ physics.ins-detastro-ph.IMhep-exhep-ph+1PRC(2021)·21 citations
25. 25*

    NMEs for $0\nu \beta \beta (0^{+}\to 2^{+})$ of two-nucleon mechanism for ${}^{76}$Ge

    Dong-Liang Fang🇨🇳 · Amand Faessler🇩🇪

    In this work we present the first beyond closure calculation for the neutrinoless double beta decay ($0\nu \beta \beta$) of ${}^{76}$Ge to the first $2^{+}$ states of ${}^{76}$Se. The isospin symmetry restored Quasi-particle random phase approximation (QRPA) method with the CD-Bonn realistic force is adopted for the nuclear structure calculations. We analyze the structure of the two nucleon mechanism nuclear matrix elements, and estimate the uncertainties from the nuclear many-body calculations. We find $g_{pp}$ plays an important role for the calculations and if quenching is included, suppression for the transition matrix element $M_{\lambda }$ is found. Our results for the transition matrix elements are about one order of magnitude larger than previous projected Hatree-Fock-Boglyubov results with the closure approximation.

    ↳ nucl-thhep-phPRC(2021)·9 citations
26. 26*

    Topological susceptibility of pure gauge theory using Density of States

    Szablocs Borsanyi🇩🇪 · Dénes Sexty🇩🇪

    The topological susceptibility of the SU(3) pure gauge theory is calculated in the deconfined phase at temperatures up to $10T_c$. At such large temperatures the susceptibility is suppressed, topologically non-trivial configurations are extremely rare. Thus, direct lattice simulations are not feasible. The density of states (DoS) method is designed to simulate rare events, we present an application of the DoS method to the problem of high temperature topological susceptibility. We reconstruct the histogram of the charge sectors that one could have obtained in a naive importance sampling. Our findings are perfectly consistent with a free instanton gas.

    ↳ hep-lathep-phhep-thPLB(2021)·37 citations
27. 27*

    Radiation signal accompanying the Schwinger effect

    I. A. Aleksandrov🇷🇺 · A. D. Panferov🇷🇺 · S. A. Smolyansky🇷🇺

    The properties of the forced oscillations of electron-positron plasma (EPP) generated from vacuum under the action of a short laser pulse are considered. Calculating the density of the conduction and polarization currents within the quantum kinetic approach, we demonstrate the presence of plasma oscillations at the frequency of the external field and its odd harmonics. It is expected that radiation generated by these plasma oscillations can be observed outside the interaction region, for example, outside the focal spot of two counterpropagating laser beams, and can serve as an indicator of the Schwinger mechanism of the EPP creation from vacuum.

    ↳ physics.plasm-phhep-phphysics.opticsPRA(2021)·14 citations
28. 28*

    Deploying heavier $\eta$ meson states: configurational entropy hybridizing AdS/QCD

    Roldao da Rocha🇧🇷

    The meson family of $\eta$ pseudoscalars is studied in the context of the AdS/QCD correspondence and the differential configurational entropy (DCE). For it, two forms of configurational-entropic Regge-like trajectories are engendered, relating the $\eta$ mesonic states excitation number to both their experimental mass spectrum in the Particle Data Group (PDG) and the DCE as well. Hence, the mass spectrum of $\eta$ pseudoscalar mesonic states, beyond the already detected states $\eta (550)$, ${\eta }^{\prime }(958)$, $\eta (1295)$, $\eta (1405)$, $\eta (1475)$, $\eta (1760)$, $\eta (2225)$, and $\eta (2320)$, is derived for any excitation number. The three first ulterior members of this family are then analyzed and also compared to existing candidates in PDG.

    ↳ hep-thhep-phPLB(2021)·19 citations
29. 29*

    Dispersion Relations in Non-Linear Electrodynamics and the Kinematics of the Compton Effect in a Magnetic Background

    M. J. Neves🇧🇷 · Jorge B. de Oliveira🇧🇷 · L. P. R. Ospedal🇧🇷 · J. A. Helayël-Neto🇧🇷

    Non-linear electrodynamic models are re-assessed in this paper to pursue an investigation of the kinematics of the Compton effect in a magnetic background. Before considering specific models, we start off by presenting a general non-linear Lagrangian built up in terms of the most general Lorentz- and gauge-invariant combinations of the electric and magnetic fields. The extended Maxwell-like equations and the energy-momentum tensor conservation are presented and discussed in their generality. We next expand the fields around a uniform and time-independent electric and magnetic backgrounds up to second order in the propagating wave, and compute dispersion relations which account for the effect of the external fields. We obtain thereby the refraction index and the group velocity for the propagating radiation in different situations. In particular, we focus on the kinematics of the Compton effect in presence of external magnetic fields. This yields constraints that relate the derivatives of the general Lagrangian with respect to the field invariants and the magnetic background under consideration. We carry out our inspection by focusing on some specific non-linear electrodynamic effective models: Hoffmann-Infeld, Euler-Heisenberg, generalized Born-Infeld and Logarithmic.

    ↳ hep-thhep-phPRD(2021)·38 citations
30. 30*

    Primordial Weibel instability

    Nahuel Mirón-Granese🇦🇷 · Esteban Calzetta🇦🇷 · Alejandra Kandus🇧🇷

    We study the onset of vector instabilities in the post-inflationary epoch of the Universe as a mechanism for primordial magnetic fields amplification. We assume the presence of a charged spectator scalar field arbitrarily coupled to gravity during Inflation in its vacuum de Sitter state. Gravitational particle creation takes place at the transition from Inflation to the subsequent Reheating stage and thus the vacuum field state becomes an excited many particles one. Consequently this state can be described as a real fluid, and we build out the hydrodynamic framework using second order theories for relativistic fluids with a relaxation time prescription for the collision integral. Given the high-temperature regime and the vanishing scalar curvature of the Universe during Reheating (radiation-dominated-type era), the fluid can be regarded as a conformal one. The large quantum fluctuations induced by the rapid transition from inflationary to effectively radiation dominated expansion become statistical fluctuations whereby both a charge excess and anisotropic pressures are produced in any finite domain. The precise magnitude of the effect for each scale is determined by the size of the averaging domain and the coupling to curvature. We look at domains which are larger than the horizon at the beginning of Reheating, but much smaller than our own horizon, and show that in a finite fraction of them the anisotropy and charge excess provide suitable conditions for a Weibel instability. If moreover the duration of reheating is shorter than the relaxation time of the fluid, then this instability can compensate or even overcome the conformal dilution of a primordial magnetic field. We show that the non-trivial topology of the magnetic field encoded in its magnetic helicity is also amplified if present.

    ↳ astro-ph.HEhep-phJCAP(2022)·5 citations
31. 31*

    Test of lepton family universality and search for lepton and baryon number violation at Belle

    D. Sahoo (on behalf of the Belle Collaboration)🇮🇳

    The electroweak penguin B decays mediated by $b\to s{\ell }^{+}{\ell }^{-}$ transitions are flavour-changing neutral current processes, and are thus sensitive to new physics owing to potential contributions of heavy particles in the quantum loop. Recently, LHCb has obtained interesting results, where the possible hints of lepton family universality violation (LFUV) could be seen. We report a new measurement of the LFUV observable $R_K$, the ratio of branching fractions of $B\to K{\mu }^{+}{\mu }^{-}$ to $B\to K{e}^{+}{e}^{-}$, based on the full data sample recorded by Belle at the ${\rm Y}(4S)$ resonance from $e^{+}{e}^{-}$ collisions produced by the KEKB collider. We also report results on lepton flavor violating $B$ decays, $B^{+}\to K^{+}{\mu }^{\pm }{e}^{\mp }$ and $B^0\to K_S^0{\mu }^{\pm }{e}^{\mp }$. The $B$-factory at KEK is also a $\tau$ factory, creating a copious amount of $\tau \tau$ pairs. We have used these data to look for lepton and baryon number violating $\tau$ decays ${\tau }^{-}\to \overline{p}{e}^{+}{e}^{-}$, $p{e}^{-}{e}^{-}$, $\overline{p}{e}^{+}{\mu }^{-}$, $\overline{p}{e}^{-}{\mu }^{+}$, $\overline{p}{\mu }^{+}{\mu }^{-}$, and $p{\mu }^{-}{\mu }^{-}$. Results of the search are also reported.

    ↳ hep-exhep-phPoS(2021)·0 citations
32. 32*

    Comparing early dark energy and extra radiation solutions to the Hubble tension with BBN

    Osamu Seto🇯🇵 · Yo Toda🇯🇵

    The shorten sound horizon scale at the recombination epoch by introducing extra energy components such as the extra radiation or early dark energy (EDE) is a simple approach to so-called the Hubble tension. We compare EDE models, an extra radiation model and an EDE and extra radiation co-existing model with paying attention to the fit to big bang nucleosynthesis (BBN). We find that a fit to BBN in EDE models also is somewhat poorer than that in the $\Lambda$CDM model, because the increased inferred baryon asymmetry leads to smaller deuterium abundance. We find that an extra radiation-EDE co-existing model indicates the largest present Hubble parameter $H_0$ between models studied. We also the examine data sets dependence, whether we include BBN or not. The difference in an extra radiation model is $3.22<N_{\mathrm{eff}}<3.49(68\%)$ for data sets without BBN and $3.16<N_{\mathrm{eff}}<3.40(68\%)$ for data sets with BBN, and is so large that the $1\sigma$ border of the larger side becomes the $2\sigma$ border.

    ↳ astro-ph.COhep-phPRD(2021)·101 citations
33. 33*

    Bounds on GUP parameters from GW150914 and GW190521

    Ashmita Das🇮🇳 · Saurya Das🇨🇦 · Noor R. Mansour🇰🇼 · Elias C. Vagenas🇰🇼

    We compute bounds on the GUP parameters for two versions of GUP using gravitational wave data from the events GW150914 and GW190521. The speed of the graviton and photon are calculated in a curved spacetime modified by GUP, assuming that these particles have a small mass. The observational bound on the difference in their speeds translates to bounds on the GUP parameters. These bounds are some of the best obtained so far in the context of quantum gravity phenomenology.

    ↳ gr-qchep-phhep-thPLB(2021)·41 citations
34. 34*

    Nuclear reactions in artificial traps

    Peng Guo🇺🇸 · Bingwei Long🇨🇳

    Coupled-channel two-particle systems bound by a harmonic trap are discussed in the present paper. We derive the formula that relates the energy levels of such trapped systems to phase shifts and inelasticity of coupled-channel reactions. The formula makes it possible to extract amplitudes of inelastic nuclear reactions from ab initio calculations of discrete levels of many-nucleon systems in a harmonic trap.

    ↳ nucl-thhep-lathep-phJ.Phys.G(2022)·25 citations
35. 35*

    Simulating Yang-Mills theories with a complex coupling

    Jan M. Pawlowski🇩🇪 · Manuel Scherzer🇩🇪 · Christian Schmidt🇩🇪 · Felix P.G. Ziegler🇩🇰 · Felix Ziesché🇩🇪

    We propose a novel simulation strategy for Yang-Mills theories with a complex coupling, based on the Lefschetz thimble decomposition. We envisage, that the approach developed in the present work, can also be adapted to QCD at finite density, and real time simulations. Simulations with Lefschetz thimbles offer a potential solution to sign problems in Monte Carlo calculations within many different models with complex actions. We discuss the structure of Generalized Lefschetz thimbles for pure Yang-Mills theories with a complex gauge coupling $\beta$ and show how to incorporate the gauge orbits. We propose to simulate such theories on the union of the tangential manifolds to the relevant Lefschetz thimbles attached to the critical manifolds of the Yang-Mills action. We demonstrate our algorithm on a (1+1)-dimensional U(1) model and discuss how, starting from the main thimble result, successive subleading thimbles can be taken into account via a reweighting approach. While we face a residual sign problem, our novel approach performs exponentially better than the standard reweighting approach.

    ↳ hep-lathep-phPRD(2021)·18 citations
36. 36*

    Avoiding the cosmological constant issue in a class of phenomenologically viable $F(R,\mathcal{G})$ theories

    Israel Quiros🇲🇽

    In this paper we investigate a class of phenomenologically viable $F(R,\mathcal{G})$ theories that are able to avoid the cosmological constant issue. While the absence of ghosts and other kinds of instability issues is of prime importance, other reasonable requirements such as vanishing effective (low curvature) cosmological constant, including the flat space as a stable vacuum solution, are also imposed on the viable models. These are free of the cosmological constant problem thanks to the following outstanding feature: the de Sitter space is an attractor of the asymptotic cosmological dynamics, with the resulting constant Hubble rate being unrelated both to the energy density of vacuum and to the low-curvature effective cosmological constant.

    ↳ gr-qcastro-ph.COhep-ph1 citation
37. 37*

    Quark matter contribution to the heat capacity of magnetized neutron stars

    E. J. Ferrer🇺🇸 · V. de la Incera🇺🇸 · P. Sanson🇺🇸

    In this paper, we find the heat capacity of the magnetic dual chiral density wave (MDCDW) phase of dense quark matter and use it to explore the feasibility of this phase for a neutron star interior. MDCDW is a spatially inhomogeneous phase of quark matter known to be favored at intermediate densities over the chirally symmetric phase and the color-flavor-locked superconducting phase. By comparing our result to the lower limit of the core heat capacity established from observations of transiently accreting neutron stars, we show that the heat capacity of MDCDW quark matter is well above that lower limit and hence cannot be ruled out. This result adds to a wealth of complementary investigations, all of which has served to strengthen the viability of a neutron star interior made of MDCDW quark matter. For completeness, we review the contributions to the heat capacity of the main neutron star ingredients at low, high and intermediate densities, with and without the presence of a magnetic field.

    ↳ nucl-thastro-ph.HEhep-phPRD(2021)·15 citations
38. 38*

    Condensates and anomaly cascade in vector-like theories

    Mohamed M. Anber🇺🇸

    We study the bilinear and higher-order fermion condensates in $4$-dimensional $SU(N)$ gauge theories with a single Dirac fermion in a general representation. Augmented with a mixed anomaly between the $0$-form discrete chiral, $1$-form center, and $0$-form baryon number symmetries (BC anomaly), we sort out theories that admit higher-order condensates and vanishing fermion bilinears. Then, the BC anomaly is utilized to prove, in the absence of a topological quantum field theory, that nonvanishing fermion bilinears are inevitable in infrared-gapped theories with $2$-index (anti)symmetric fermions. We also contrast the BC anomaly with the $0$-form anomalies and show that it is the former anomaly that determines the infrared physics; we argue that the BC anomaly lurks deep to the infrared while the $0$-form anomalies are just variations of local terms. We provide evidence of this assertion by studying the BC anomaly in vector-like theories compactified on a small spacial circle. These theories are weakly-coupled, under analytical control, and they admit a dual description in terms of abelian photons that determine the deep infrared dynamics. We show that the dual photons talk directly to the $1$-form center symmetry in order to match the BC anomaly, while the $0$-form anomalies are variations of local terms and are matched by fiat. Finally, we study the fate of the BC anomaly in the compactified theories when they are held at a finite temperature. The effective field theory that describes the low-energy physics is $2$-dimensional. We show that the BC anomaly cascades from $4$ to $2$ dimensions.

    ↳ hep-thhep-lathep-phJHEP(2021)·19 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.