Wed·Nov 10, 2021Wednesday·November 10, 2021

1. 01*

   Electroweak signatures of gauge-mediated supersymmetry breaking in multiple hidden sectors

   Diogo Buarque Franzosi🇸🇪 · Gabriele Ferretti🇸🇪 · Ellen Riefel🇸🇪 · Sara Strandberg🇸🇪

   This paper discusses electroweak collider signatures of the NMSSM with multiple-sector gauge mediation. We focus on the production of neutralinos and charginos which cascade decay into standard model particles and lighter supersymmetric particles, with special emphasis on final states with multiple photons. A search strategy for signatures with at least three photons is presented and compared with current exclusion limits based on two-photon searches. We show that in many regions of the parameter space our strategy gives stronger constraints than the existing two-photon analysis for these models.

   hep-phhep-exJHEP(2022)·3 citations
2. 02*

   Perturbative structure of two- and four-point functions of color charge in a non-Gaussian small-$x$ action

   Andre V. Giannini🇧🇷 · Yasushi Nara🇯🇵

   We compute the perturbative expansion of the two- and four-point functions of color charges in the Color Glass Condensate framework considering the quartic correction to the McLerran-Venugopalan (MV) model of Gaussian color charge fluctuations. Expressions for these correlators in the perturbative expansion for small and large non-Gaussian color charge fluctuations are derived for arbitrary orders in perturbation theory. We explicitly show that the perturbative series does not converge at higher orders as expected. We apply the Borel-Padé resummation method to our problem to construct a convergent series. It is shown that the fully non-perturbative solution can be described by the Borel-Padé approximants constructed from the first few terms of the perturbative series for small non-Gaussian fluctuations.

   hep-phnucl-thEPJC(2022)·3 citations
3. 03*

   Lepton flavor violating decays $\tau \to Pl$ in the $U(1{)}_X$SSM model

   Tong-Tong Wang🇨🇳 · Shu-Min Zhao🇨🇳 · Xing-Xing Dong🇨🇳 · Lu-Hao Su🇨🇳 · Ze-Ning Zhang🇨🇳 · Wei Li🇨🇳 · Tai-Fu Feng🇨🇳

   $U(1{)}_X$SSM is the extension of the minimal supersymmetric standard model(MSSM) and its local gauge group is $SU(3{)}_C\times SU(2{)}_L\times U(1{)}_Y\times U(1{)}_X$. To obtain this model, three singlet new Higgs superfields and right-handed neutrinos are added to MSSM. In the framework of $U(1{)}_X$SSM, we study lepton flavor violating decays $\tau \to Pl(P=\pi ,\eta ,{\eta }^{\prime };l=\mu ,e)$. According to the latest experimental data of $\tau \to Pe$ and $\tau \to P\mu$, the influence of different sensitive parameters on the results is analyzed to make a reasonable prediction for future experiments. From the numerical analysis, the non-diagonal elements which correspond to the generations of the initial lepton and final lepton are main sensitive parameters and lepton flavor violation(LFV) sources. This work can provide a basis for finding the existence of new physics(NP).

   hep-phJHEP(2022)·12 citations
4. 04*

   Electromagnetic Dalitz Decays of $D_{(s)}^{\ast }$ Mesons

   Yinghua Tan🇨🇳 · Zhenyu Zhang🇨🇳 · Xiang Zhou🇨🇳

   Rare electromagnetic decays of charmed mesons are useful laboratories to explore the structure of hadronic states and the interactions between photon and charmed mesons, to test the chiral perturbation theory in flavor sector and to search for new physics including dark photons. In this paper, we calculate the relative branching ratios of electromagnetic Dalitz decays $D_{(s)}^{\ast }\to D_{(s)}{\ell }^{+}{\ell }^{-}$ to their corresponding radiative decays $D_{(s)}^{\ast }\to D_{(s)}\gamma$, the dileptonic invariant mass spectra and the leptonic angular distributions with transition form factor in Vector-Meson Dominance model, where $D_{(s)}^{\ast }$ represents $D^{\ast }(2007{)}^0$, $D^{\ast }(2010{)}^{\pm }$, $D^{\ast }(2640{)}^{\pm }$, $D_s^{\ast \pm }$, $D_{s1}^{\ast }(2700{)}^{\pm }$ and $D_{s1}^{\ast }(2860{)}^{\pm }$.

   hep-phInt.J.Mod.Phys.A(2022)·5 citations
5. 05*

   Effect of fluctuations on the Geodesic rule for topological defect formation

   Sanatan Digal🇮🇳 · Vinod Mamale🇮🇳

   At finite temperature, the field along a linear stretch of correlation length size is supposed to trace the shortest path in the field space given the two end point values, known as the Geodesic rule. In this study, we compute the probability that, the field variations over distances of correlation length follow this rule in theories with $O(2)$ global symmetry. We consider a simple ferromagnetic $O(2)$ spin-model and a complex ${\varphi }^4$ theory. The computations are carried out on an ensemble of equilibrium configurations, generated using Monte Carlo simulations. The numerical results suggest significant deviation to the Geodesic rule, relevant for formation of topological defects during quench in 2nd order phase transition. Also for the case of $O(2)-$spins in two dimensions, distribution and density of vortices, have been studied. It is found that, for quench temperatures close to the transition point, the Kibble-Zurek Mechanism underestimates equilibrium density of defects. The exponents corresponding to width of the distributions, are found to be smaller than Kibble Mechanism estimates and match only when there is no deviation from the geodesic rule.

   hep-phcond-mat.otherhep-thMod.Phys.Lett.A(2022)·0 citations
6. 06*

   Collective neutrino oscillations in moving and polarized matter

   Zekun Chen🇷🇺 · Konstantin Kouzakov🇷🇺 · Yu-Feng Li🇨🇳 · Vadim Shakhov🇷🇺 · Konstantin Stankevich🇷🇺 · Alexander Studenikin🇷🇺

   We consider neutrino evolution master equations in dense moving and polarized matter consisted of electrons, neutrons, protons and neutrinos. We also take into account the neutrino magnetic moment interaction with a magnetic field. We point out the mechanisms responsible for the neutrino spin precession and provide the expressions for the corresponding interaction Hamiltonians that should be taken into account in theoretical treatments of collective neutrino oscillations.

   hep-phastro-ph.HEJ.Phys.Conf.Ser.(2021)·0 citations
7. 07*

   $Z_{cs}$ states from the $D_s^{\ast }{\bar{D}}^{\ast }$ and $J/\psi K^{\ast }$ coupled channels: Signal in $B^{+}\to J/\psi \varphi K^{+}$ decay

   Natsumi Ikeno🇯🇵 · Raquel Molina🇪🇸 · Eulogio Oset🇪🇸

   We study the $D_s^{\ast }{\bar{D}}^{\ast }$ system in connection with the $J/\psi K^{\ast }$ in coupled channels and observe that, within reasonable values of the cut-off used to regularize the loops, the system does not develop a bound state. However, the $J^P=2^{+}$ channel has enough attraction to create a strong cusp structure that shows up in the $J/\psi K^{+}$ invariant mass distribution in the $B^{+}\to J/\psi \varphi K^{+}$ decay at the $D_s^{\ast }{\bar{D}}^{\ast }$ threshold. Such structure is visible in the experimental $B^{+}\to J/\psi \varphi K^{+}$ and ${\bar{B}}^0\to J/\psi K^{+}{K}^{-}$ decays, with small statistics, and our results should stimulate further measurements around this region, given the fact that cusp effects provide as valuable information on hadron dynamics as resonances themselves.

   hep-phPRD(2022)·17 citations
8. 08*

   $X$ structures in $B^{+}\to J/\psi \varphi K^{+}$ as one-loop and double-triangle threshold cusps

   Satoshi X. Nakamura (Univ. of Science and Technology of China)🇨🇳

   The LHCb data on $B^{+}\to J/\psi \varphi K^{+}$ show four peaks and three dips in the $J/\psi \varphi$ invariant mass distribution, and the peaks are interpreted as $X(4140)$, $X(4274)$, $X(4500)$ and $X(4685)/X(4700)$ resonance contributions. Interestingly, all the peaks and dips are located at (or close to) $D_s^{\ast }{\bar{D}}_s^{(\ast )}$, $D_{s0}^{\ast }(2317){\bar{D}}_s^{(\ast )}$, $D_{s1}(2536){\bar{D}}_s^{(\ast )}$, and ${\psi }^{\prime }\varphi$ thresholds. These coincidences suggest a close connection between the structures and the thresholds, which however has not been seriously considered in previous theoretical studies on the $X$ structures. In fact, if we utilize this connection and interpret the $X$ structures as common $s$-wave threshold cusps, we face a difficulty: $X(4274)$ and $X(4500)$ have spin-parity that conflict with the experimentally determined ones. In this work, we introduce double triangle mechanisms that cause threshold cusps significantly sharper than the ordinary one-loop ones of the same spin-parity. We demonstrate that all the $X$ and dip structures are well described by a combination of one-loop and double-triangle threshold cusps, thereby proposing a novel interpretation of the $X$ and dip structures.

   hep-phhep-exnucl-thPLB(2022)·12 citations
9. 09*

   Power corrections to the CP-violation parameter ${\epsilon }_K$

   M. Ciuchini🇮🇹 · E. Franco🇮🇹 · V. Lubicz🇮🇹 · G. Martinelli🇮🇹 · L. Silvestrini🇮🇹 · C. Tarantino🇮🇹

   We present the calculation of the short-distance power corrections to the CP-violation parameter ${\epsilon }_K$ coming from dimension-8 operators in the $\Delta S=2$ effective Hamiltonian. A first estimate of this contribution, obtained for large-$N_c$ and in the chiral limit, was provided in ref. [arXiv:hep-ph/0406094]. Here we evaluate and include the $\mathcal{O}(m_K^2/m_c^2)$ and $\mathcal{O}({\Lambda }_{QCD}^2/m_c^2)$ contributions that, a priori, could induce $\mathcal{O}(1)$ corrections to previous estimates, as $m_K$ is numerically of order ${\Lambda }_{QCD}$. Our computation shows that there are several dimension-8 operators besides the one considered before. Their effect on ${\epsilon }_K$, however, accidentally cancels out to a large extent, leaving the final correction at the level of 1%.

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

    Two-parton scattering in the high-energy limit: climbing two- and three-Reggeon ladders

    Leonardo Vernazza🇮🇹 · Giulio Falcioni🇬🇧 · Einan Gardi🇬🇧 · Niamh Maher🇬🇧 · Calum Milloy🇮🇹

    We review recent progress on the calculation of scattering amplitudes in the high-energy limit. We start by illustrating the shockwave formalism, which allows one to calculate amplitudes as iterated solutions of rapidity evolution equations. We then focus on our recent results regarding $2\to 2$ parton scattering. We present the calculation of the imaginary part of the amplitude, at next-to-leading logarithmic accuracy in the high-energy logarithms, formally to all orders, and in practice to 13 loops. We then discuss the computation of the real part of the amplitude at next-to-next-to-leading logarithmic accuracy and through four loops. Both computations are carried in full colour, and provide new insight into the analytic structure of scattering amplitudes and their infrared singularity structure.

    hep-phSciPost Phys.Proc.(2022)·8 citations
11. 11*

    Linking the $R_{K^{(\ast )}}$ anomalies to the Hubble tension via a single right-handed neutrino

    Wen-Feng Duan🇨🇳 · Shao-Ping Li🇨🇳 · Xin-Qiang Li🇨🇳 · Ya-Dong Yang🇨🇳

    The updated measurements from the LHCb and SH0ES collaborations have respectively strengthened the deviations of the ratio $R_K$ in rare semi-leptonic $B$-meson decays and the present-day Hubble parameter $H_0$ in the Universe, implying tantalizing hints of new physics beyond the Standard Model. In this paper, we consider a simple flavor-specific two-Higgs-doublet model, where the long-standing $R_{K^{(\ast )}}$ anomalies can be addressed by a one-flavor right-handed neutrino. One of the intriguing predictions resulting from the parameter space for the $R_{K^{(\ast )}}$ resolution under flavor- and collider-physics constraints points toward a shift of the effective neutrino number, $\Delta N_{\mathrm{eff}}=N_{\mathrm{eff}}-N_{\mathrm{eff}}^{\mathrm{SM}}$, as favored to ease the $H_0$ tension. Depending on whether the neutrino is of Dirac or of Majorana type, we show that the resulting shift is $\Delta N_{\mathrm{eff}}\simeq 1.0$ for the former and $\Delta N_{\mathrm{eff}}\simeq 0.5$ for the latter case, respectively. While the Dirac case is disfavored by the CMB polarization measurements, the Majorana solution is consistent with the recent studies via a combined data set from various sources. Consequently, such a simple flavor-specific two-Higgs-doublet model provides a link between the $R_{K^{(\ast )}}$ anomalies and the $H_0$ tension, which in turn can be readily verified or falsified by the upcoming measurements.

    hep-phhep-exCPC(2023)·9 citations
12. 12*

    Production rate and ellipticity of lepton pairs from a rotating hot and dense QCD medium

    Minghua Wei🇨🇳 · Chowdhury Aminul Islam🇨🇳 · Mei Huang🇨🇳

    Using a current-current correlation function (CF), the photon polarization tensor is calculated for a rotating hot and dense QCD medium. The spectral function (SF) and the dilepton rate (DR) are estimated therefrom. Numerical results show that both SF and DR are enhanced in a rotating medium, especially in a low invariant mass region. SF and DR are also explored in the consequences of the interplay among the angular velocity, temperature and chemical potential. We also estimated the electromagnetic screening by calculating the Debye mass and it shows a suppression for a rotating QCD medium. The most interesting observation is the azimuthal anisotropy of the dilepton production, i.e, the elliptic flow $v_2$ of the lepton pair induced by the rotation as an external field. The competition between the centrifugal effect and the spin polarization effect due to rotation results in a convex down behaviour of the elliptic flow as a function of the transverse momentum in a relatively large magnitude of angular velocity. It is noticed that quark spin polarization induces a negative $v_2$ in the case of large angular velocity.

    hep-phnucl-thPRD(2022)·15 citations
13. 13*

    Exploring the effect of hadron cascade-time on particle production in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV through a multi-phase transport model

    Girija Sankar Pradhan🇮🇳 · Rutuparna Rath🇮🇳 · Ronald Scaria🇮🇳 · Raghunath Sahoo🇮🇳

    Heavy-ion collisions at ultra-relativistic energies provide extreme conditions of energy density and temperature to produce a deconfined state of quarks and gluons. Xenon (Xe) being a deformed nucleus further gives access to the effect of initial geometry on final state particle production. This study focuses on the effect of nuclear deformation and hadron cascade-time on the particle production and elliptic flow using A Multi-Phase Transport (AMPT) model in Xe+Xe collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV. We explore the effect of hadronic cascade-time on identified particle production through the study of $p_{\mathrm{T}}$-differential particle ratios. The effect of hadronic cascade-time on the generation of elliptic flow is studied by varying the cascade-time between 5 and 25 fm/$c$. This study shows the final state interactions among particles generate additional anisotropic flow with increasing hadron cascade-time, especially at very low and high-$p_{\mathrm{T}}$.

    hep-phhep-exnucl-exnucl-thPRC(2022)·9 citations
14. 14*

    First saturation correction in high energy proton-nucleus collisions: Part III. Ensemble averaging

    Ming Li🇺🇸 · Vladimir V. Skokov🇺🇸

    In high energy proton-nucleus collisions, the gluon saturation effects from the nucleus are fully incorporated into the light-like Wilson lines. The gluon saturation effects from the proton, which are anticipated to be important either in the extreme high energy limit or towards the dense-dense (nucleus-nucleus) collision regimes, have been studied perturbatively within the Color Glass Condensate effective theory in previous papers of this series. A configuration-by-configuration expression for the single inclusive semi-hard gluon production including the first saturation correction was obtained. In this paper, we perform ensemble averaging in the McLerran-Venugopalan model and the Dipole Approximation. We find that, in the saturation correction, the effects of the initial state interactions are negligible while the final state interactions play most important role and give a positive-valued contribution to the semi-hard gluon spectrum. Furthermore, we show that the single gluon spectrum scales approximately $1/k_{\perp }^4$ at small $k_{\perp }$, suggesting that a resummation of higher order saturation corrections is required to regulate the infrared region of the gluon spectrum.

    hep-phnucl-thJHEP(2022)·10 citations
15. 15*

    Testing Lepton Flavor Universality with Pion, Kaon, Tau, and Beta Decays

    Douglas Bryman🇨🇦 · Vincenzo Cirigliano🇺🇸 · Andreas Crivellin🇨🇭 · Gianluca Inguglia🇦🇹

    We present an overview of searches fo violation of lepton flavor universality with focus on low energy precision probes using pions, kaons, tau leptons, and nuclear beta decays. The current experimental results are reviewed, the theoretical status within the context of the Standard Model is summarized, and future prospects (both experimental and theoretical) are discussed. We review the implications of these measurements for physics beyond the Standard Model by performing a global model-independent fit to modified $W$ couplings to leptons and four-fermion operators. We also discuss new physics in the context of simplified models and review Standard Model extensions with focus on those which can explain a possible deviation from unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

    hep-phhep-exhep-latnucl-ex+1Ann.Rev.Nucl.Part.Sci.(2022)·71 citations
16. 16*

    Universality (beyond leading log) of soft radiative corrections to $\hat{q}$ in $p_{\perp }$ broadening and energy loss

    Peter Arnold🇺🇸

    It has been known for many years that soft radiation can give potentially large double-logarithm corrections to $p_{\perp }$ broadening of a high-energy particle traveling through QCD matter, but that this soft radiation correction can be absorbed into an effective value ${\hat{q}}_{\mathrm{eff}}$ for the medium $p_{\perp }$-broadening parameter $\hat{q}$. Here "soft" means high energy compared to medium scales but soft compared to the original high-energy particle traveling through the medium. A similar situation arises in the case of soft corrections to hard splitting of a high-energy particle, such as hard $g\to gg$, where double logarithms can also be absorbed using the same effective ${\hat{q}}_{\mathrm{eff}}$. In this paper, I study whether the same holds true for potentially large, subleading, *single*-logarthim corrections. The correspondence is more indirect for single logarithms, but I show (in the large-$N_{\mathrm{c}}$ limit) that single logarithms from soft radiation in the case of $p_{\perp }$ broadening also determine the single logarithms from soft radiative corrections to hard $g\to gg$ splitting. Along the way, there is an interesting variation of the original BDMPS-Z calculation of splitting rates in the $\hat{q}$ approximation. I also discuss how, for soft-radiative corrections to hard splitting processes, there are two different types of "${\hat{q}}_{\mathrm{eff}}$" that come into play, which differ by "$i\pi$" terms that multiply single logarithms.

    hep-phnucl-thJHEP(2022)·18 citations
17. 17*

    Coupled-channel analysis of pion- and eta-electroproduction with the Jülich-Bonn-Washington model

    Maxim Mai🇺🇸 · Michael Döring🇺🇸 · Carlos Granados🇺🇸 · Helmut Haberzettl🇺🇸 · Jackson Hergenrather🇺🇸 · Ulf-G. Meißner🇩🇪 · Deborah Rönchen🇩🇪 · Igor Strakovsky🇺🇸 · Ron Workman🇺🇸

    Pion and eta electroproduction data are jointly analyzed for the first time, up to a center-of-mass energy of 1.6 GeV. The framework is a dynamical coupled-channel model, based on the recent Jülich-Bonn-Washington analysis of pion electroproduction data for the same energy range. Comparisons are made to a number of single-channel eta electroproduction fits. By comparing multipoles of comparable fit quality, we find some of these amplitudes are well determined over the near-threshold region, while others will require fits over an extended energy range.

    ↳ nucl-thhep-phnucl-exPRC(2022)·31 citations
18. 18*

    The CLIC potential for new physics

    Jan Klamka🇵🇱

    The Compact Linear Collider (CLIC) is a mature option for a future electron-positron collider operating at centre-of-mass energies of up to 3 TeV. It incorporates a novel two-beam acceleration technique offering accelerating gradient of up to 100 MeV/m. CLIC would be built and operated in a staged approach with three centre-of-mass energy stages currently assumed to be 380 GeV, 1.5 TeV, and 3 TeV. The first CLIC stage will be focused on precision Higgs and top quark measurements. The so called "Higgs-strahlung" process ($e^{+}{e}^{-}\to \mathrm{ZH}$) is a key for a model independent measurement of Higgs boson decays and extraction of its couplings. Precision top quark measurements will include the pair-production threshold scan, which is assumed to be the most precise method for the top-quark mass determination. The two subsequent energy stages will allow for extended Standard Model studies, including the direct measurement of the Higgs self-coupling and the top Yukawa coupling, but their main goals will be to search for signatures of Beyond the Standard Model phenomena. Presented in this contribution is a selection of recent results showing sensitivity of CLIC experiment to diverse BSM physics scenarios. Compared with hadron colliders, the low background conditions at CLIC provide extended discovery potential, in particular for the production through electroweak and/or Higgs boson interactions. This includes scenarios with extended scalar sectors, also motivated by dark matter, which can be searched for using associated production processes or cascade decays involving electroweak gauge bosons. In a wide range of models, new particles can be discovered almost up to the kinematic limit while the indirect search sensitivity extends up to $\mathcal{O}(100)$ TeV scales.

    ↳ hep-exhep-phPoS(2022)·7 citations
19. 19*

    Lattice Lindblad simulation

    Tomoya Hayata🇯🇵 · Yoshimasa Hidaka🇯🇵 · Arata Yamamoto🇯🇵

    We perform the real-time lattice simulation of an open quantum system, which is based on the Schwinger-Keldysh path integral representation of the Lindblad formalism. Although the real-time simulation generally suffers from the sign problem, there exist a few exceptional cases. We focus on a sign-problem-free system of a non-relativistic spinless fermion and analyze time evolution under driving and dissipation.

    ↳ hep-lathep-phhep-thquant-phPTEP(2022)·19 citations
20. 20*

    Can we make sense of dissipation without causality?

    Lorenzo Gavassino🇵🇱

    Relativity opens the door to a counter-intuitive fact: a state can be stable to perturbations in one frame of reference, and unstable in another one. For this reason, the job of testing the stability of states that are not Lorentz-invariant can be very cumbersome. We show that two observers can disagree on whether a state is stable or unstable only if the perturbations can exit the light-cone. Furthermore, we show that, if a perturbation exits the light-cone, and its intensity changes with time, due to dissipation, then there are always two observers that disagree on the stability of the state. Hence, ''stability'' is a Lorentz-invariant property of dissipative theories if and only if the principle of causality is respected. We present 14 applications to physical problems from all areas of relativistic physics, ranging from theory to simulation.

    ↳ gr-qcastro-ph.HEhep-phhep-thPRX(2022)·107 citations
21. 21*

    How perturbative QCD constrains the Equation of State at Neutron-Star densities

    Oleg Komoltsev🇳🇴 · Aleksi Kurkela🇳🇴

    We demonstrate in a general and analytic way how high-density information about the equation of state (EoS) of strongly interacting matter obtained using perturbative Quantum Chromodynamics (pQCD) constrains the same EoS at densities reachable in physical neutron stars. Our approach is based on utilizing the full information of the thermodynamic potentials at the high-density limit together with thermodynamic stability and causality. This requires considering the pressure as a function of chemical potential $p(\mu )$ instead of the commonly used pressure as a function of energy density $p(ϵ)$. The results can be used to propagate the pQCD calculations reliable around 40$n_s$ to lower densities in the most conservative way possible. We constrain the EoS starting from only few times the nuclear saturation density $n\gtrsim 2.2n_s$ and at $n=5n_s$ we exclude at least 65% of otherwise allowed area in the $(ϵ-p)$-plane. This provides information complementary to astrophysical observations that should be taken into account in any complete statistical inference study of the EoS. These purely theoretical results are independent of astrophysical neutron-star input, and hence, they can also be used to test theories of modified gravity and BSM physics in neutron stars.

    ↳ nucl-thastro-ph.HEhep-phPRL(2022)·234 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.