Fri·May 24, 2019Friday·May 24, 2019

1. 01*

   Estimation of attractive and repulsive interactions from the fluctuation observables at RHIC using van der Waals hadron resonance gas Model

   Subhasis Samanta🇮🇳 · Bedangadas Mohanty🇮🇳

   Experimental data on the moments of net-proton distribution in central Au-Au collisions for various center of mass energies ($\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$) measured by the STAR collaboration at the Relativistic Heavy-Ion Collider (RHIC) are compared to the corresponding results from a van der Waals type interacting hadron resonance gas (VDWHRG) model. The parameters representing the attractive and repulsive interactions in the VDWHRG model have been extracted by fitting the ${\sigma }^2$/$M$, $S\sigma$ and $\kappa {\sigma }^2$, where $M$ is the mean, $\sigma$ is the standard deviation, $S$ is the skewness and $\kappa$ the kurtosis of the net-proton distribution. Considering all the three moment products we observe that the strength of the repulsive interactions increases with decrease in $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 200 to 19.6 GeV while the strength of the attractive interaction is of the similar magnitude. For $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 11.5 and 7.7 GeV there is drop in the strength of both attractive and repulsive interactions relative to $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 19.6 GeV. On the other hand, if we consider only the higher order moment products, $S\sigma$ and $\kappa {\sigma }^2$, which are more sensitive to critical point physics, a segregation with respect to the strength of the attractive parameter is observed. The data for $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 19.6 and 27 GeV supports a larger attractive strength compared to other energies. For this latter case, the repulsive interaction values are of similar order for most of the beam energies studied, except for 7.7 GeV where the parameter value is not well constrained due to large uncertainties.

   hep-phnucl-th2 citations
2. 02*

   How to detect the lightest glueball

   B. P. Kosyakov🇷🇺 · E. Yu. Popov🇷🇺 · M. A. Vronsky

   We suggest a procedure of the lightest glueball detection in a head-on collision of photons whose center-of-mass energy is in the range $1.3-2$ GeV. Recent evidence for the scattering of light by light in experiments at the Large Hadron Collider is used as a phenomenological basis of our suggestion. With this evidence, the cross section of the lightest glueball creation in the $\gamma \gamma$ collisions is estimated to be $\sim 60$nb. The predominant mode of the lightest glueball decay, predicted from the gauge/gravity duality, proves to be the decay into two neutral vector mesons ${\rho }^0{\rho }^0$. Because ${\rho }^0$ decays into ${\pi }^{+}{\pi }^{-}$, a drastic increase in the ${\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ yield is expected as the center-of-mass energy of the colliding photons approaches the value of the lightest glueball mass. This fact may be regarded as the unique signature of the lightest glueball detection.

   hep-phhep-thJ.Exp.Theor.Phys.(2021)·2 citations
3. 03*

   Bounding the Charm Yukawa

   Nina M. Coyle🇺🇸 · Carlos E.M. Wagner🇺🇸 · Viska Wei🇺🇸

   The study of the properties of the observed Higgs boson is one of the main research activities in High Energy Physics. Although the couplings of the Higgs to the weak gauge bosons and third generation quark and leptons have been studied in detail, little is known about the Higgs couplings to first and second generation fermions. In this article, we study the charm quark Higgs coupling in the so-called $\kappa$ framework. We emphasize the existence of specific correlations between the Higgs couplings that can render the measured LHC Higgs production rates close to the SM values in the presence of large deviations of the charm coupling from its SM value, ${\kappa }_c=1$. Based on this knowledge, we update the indirect bounds on ${\kappa }_c$ through a fit to the precision Higgs measurements at the LHC. We also examine the limits on ${\kappa }_c$ arising from the radiative decay $H\to J/\psi +\gamma$, the charm quark-associated Higgs production, charm quark decays of the Higgs field and charge asymmetry in $W^{\pm }+H$ production. Estimates for the future LHC sensitivity on ${\kappa }_c$ at the high luminosity run are provided.

   hep-phPRD(2019)·31 citations
4. 04*

   Associated production of Higgs boson with a photon at electron-positron colliders

   Mehmet Demirci🇹🇷

   A complete one-loop prediction for the single production of the neutral Higgs bosons in association with a photon in electron-positron collisions is presented in the framework the minimal supersymmetric standard model (MSSM), paying special attention to the individual contribution from each type of diagram. This process has no amplitude at tree level and is hence directly sensitive to one-loop impacts and the underlying dynamics of Higgs. To investigate the effect of the new physics, four different scenarios, which include a Higgs boson with mass and couplings consistent with those of the discovered Higgs boson and a considerable part of parameter space allowed by the bounds from the searches for additional Higgs bosons and sparticles, are chosen in the MSSM. The dependence of the cross section in both the standard model(SM) and MSSM on the center-of-mass energy is examined by considering the polarizations of the initial electron and positron beams. The effect of individual contributions from each type of one-loop diagram on the total cross section is also investigated in detail. Furthermore, the total cross sections of $e^{-}{e}^{+}\to \gamma h^0$ as well as $e^{-}{e}^{+}\to \gamma A^0$ are scanned over the plane $m_A-\tan \beta$ for each scenario. The full one-loop contributions are crucial for the analysis of beyond the SM physics at a future electron-positron collider.

   hep-phPRD(2019)·9 citations
5. 05*

   Charged Higgs bosons in the NMSSM under current LHC constraints

   Zhaoxia Heng🇨🇳 · Lin Guo🇨🇳 · Pengqiang Sun🇨🇳 · Wei Wei🇨🇳

   Charged Higgs boson is a crucial prediction of new physics beyond the SM. In this work, we perform a comprehensive scan over the parameter space of NMSSM considering various experimental constraints including the direct search limits from the 13 TeV LHC, and consider the scenario that the next-to-lightest CP-even Higgs boson is SM-like. We find that the masses of charged Higgs bosons can be as light as 350 GeV, the lightest CP-even Higgs boson $h_1$ is predominantly singlet and can be as light as 48 GeV, and the lightest CP-odd Higgs boson $a_1$ is also singlet-dominated and can be as light as 82 GeV. The charged Higgs bosons mainly decay to $t\bar{b}$ or $\bar{t}b$, but the branching ratio of the exotic decays $H^{\pm }\to W^{\pm }{h}_1$ and $H^{\pm }\to W^{\pm }{a}_1$ can maximally reach to 20\% and 11\%, respectively, which can be used to distinguish the NMSSM from MSSM. Such a heavy charged Higgs boson is unaccessible at the 13 TeV LHC with a luminosity of 36.1 $\mathrm{f}{\mathrm{b}}^{-1}$ and its detection needs higher energy and/or higher luminosity.

   hep-phMod.Phys.Lett.A(2019)·3 citations
6. 06*

   Probe Charm Yukawa at the future $e^{-}p$ and $e^{+}{e}^{-}$ colliders

   Ruibo Li🇨🇳 · Bo-Wen Wang🇨🇳 · Kai Wang🇨🇳 · Xiaoyuan Zhang🇨🇳 · Zhenyu Zhou🇨🇳

   Large Hadron Collider (LHC) has provided direct evidence of Yukawa couplings between the third generation charged fermions and the 125 GeV Higgs boson. Whether the first two generation charged fermions arise from exactly the same mechanism becomes the next interesting question. Therefore, direct measurements of charm or muon Yukawa couplings will be crucial to answering this puzzle. The charm Yukawa measurement at the LHC suffers from severe QCD background and it is extremely difficult to reach the sensitivity. In this paper, we compare the potential of probing charm Yukawa coupling at the two proposed future "Higgs Factory" experiments, the Large Hadron electron Collider (LHeC) and Circular electron positron collider (CEPC). At the LHeC, Higgs bosons will be produced via weak boson fusion and the energetic forward jet may suppress the background significantly. However, due to huge $\gamma -g$ scattering background, the potential of LHeC search is still limited. With $-80\%$ polarized electron beam of 60 GeV, the signal significance can only reach $2\sigma$ for ${\kappa }_c\simeq 1$ with a 3 ab${}^{-1}$ integrated luminosity. In comparison, measurement at the CEPC can then reach $8.0\sigma$ for ${\kappa }_c\simeq 1$ with a 2 ab${}^{-1}$ of data.

   hep-phPRD(2019)·7 citations
7. 07*

   NRQCD colour-octet expansion vs LHC quarkonium production: signs of a hierarchy puzzle?

   Pietro Faccioli🇵🇹 · Carlos Lourenco🇨🇭

   The observation of unpolarized quarkonium production in high energy pp collisions, at mid rapidity, implies a significant violation of the non-relativistic QCD (NRQCD) velocity scaling rules. A precise experimental confirmation of this picture could definitely rule out the current formulation of the factorization expansion. This conclusion relies on current perturbative determinations of the short-distance kinematic factors and may be reverted if improved calculations would modify, in a very specific way, their transverse momentum dependences. That solution would result, however, in a full degeneracy in the presently assumed basis of ${}^{2S+1}{L}_J$ Fock states. Therefore, whatever the outcome, improved polarization measurements will challenge and improve our fundamental understanding of quarkonium production.

   hep-phEPJC(2019)·7 citations
8. 08*

   Thermodynamic Evolution of Secluded Vector Dark Matter: Conventional WIMPs and Nonconventional WIMPs

   Kwei-Chou Yang🇹🇼

   The secluded dark matter resides within a hidden sector and self-annihilates into lighter mediators which subsequently decay to the Standard Model (SM) particles. Depending on the coupling strength of the mediator to the SM, the hidden sector can be kinetically decoupled from the SM bath when the temperature drops below the mediator's mass, and the dark matter annihilation cross section at freeze-out is thus possible to be boosted above the conventional value of weak interacting massive particles. We present a comprehensive study on thermodynamic evolution of the hidden sector from the first principle, using the simplest secluded vector dark matter model. Motivated by the observation of Galactic center gamma-ray excess, we take two mass sets $\sim \mathcal{O}(80\text{GeV})$ for the dark matter and mediator as examples to illustrate the thermodynamics. The coupled Boltzmann moment equations for number densities and temperature evolutions of the hidden sector are numerically solved. The formalism can be easily extended to a general secluded dark matter model. We show that a long-lived mediator can result in a boosted dark matter annihilation cross section to account for the relic abundance. We further show the parameter space which provides a good fit to the Galactic center excess data and is compatible with the current bounds and LUX-ZEPLIN projected sensitivity. We find that the future observations of dwarf spheroidal galaxies offer promising reach to probe the most relic allowed parameter space relevant to the boosted dark matter annihilation cross section.

   hep-phastro-ph.COJHEP(2019)·14 citations
9. 09*

   Noncommutative approach to disclose a Higgs group

   M. A. De Andrade🇧🇷 · C. Neves🇧🇷

   A noncommutative(NC) version for a global $O(N)$ scalar field theory is proposed and an alternative investigation about how noncommutative drives spontaneous symmetry breaking (SSB) is explored. Indeed, we show that the noncommutativity plays an important role in such mechanism, i.e., it is possible to show that there is a Higgs group with no more than two Higgs bosons. In this scenario, we establish two mutually exclusive options: one Higgs boson with mass at 125 GeV and other at 750 GeV -- 2 TeV excess does not imply a 2 TeV mass resonance -- or two Higgs bosons with mass-degenerate near 125~GeV, where 2 TeV and 750 GeV excesses do not imply a 2 TeV and 750 GeV masses resonance.

   hep-phhep-th0 citations
10. 10*

    New Long Lived Particles Searches in Heavy Ion Collisions at the LHC

    Marco Drewes🇧🇪 · Andrea Giammanco🇧🇪 · Jan Hajer🇧🇪 · Michele Lucente🇧🇪

    We show that heavy ion collisions at the LHC provide a promising environment to search for signatures with displaced vertices in well-motivated New Physics scenarios. Compared to proton collisions, they offer several advantages, i) the number of parton level interactions per collision is larger, ii) there is no pile-up, iii) the lower instantaneous luminosity compared to proton collisions allows to operate the LHC experiments with very loose triggers, and iv) there are new production mechanisms that are absent in proton collisions. In the present work we focus on the third point and show that the modification of the triggers alone can increase the number of observable events by orders of magnitude if the long lived particles are predominantly produced with low transverse momentum. Our results show that collisions of ions lighter than lead are well-motivated from the viewpoint of searches for New Physics. We illustrate this for the example of heavy neutrinos in the Neutrino Minimal Standard Model.

    hep-phPRD(2020)·29 citations
11. 11*

    Dynamical origin of flavor hierarchies in a warped extra dimension

    Aqeel Ahmed🇧🇪 · Adrian Carmona🇩🇪 · Javier Castellano Ruiz🇩🇪 · Yi Chung🇩🇪 · Matthias Neubert🇩🇪

    Extensions of the Standard Model featuring a warped extra dimension compactified on an $S^1/{\mathbb{Z}}_2$ orbifold, in which the fermions and gauge bosons live in the bulk of the fifth dimension, offer one of the most compelling mechanisms for addressing both the hierarchy problem and the flavor puzzle of the Standard Model. However, the five-dimensional mass terms of bulk fermions must be odd functions on the orbifold, and as such they should be described by a field depending on the coordinate of the extra dimension. We demonstrate the feasibility of dynamically generating these fermion bulk masses with a bulk scalar field in warped extra dimensions. The bulk scalar acquires a vacuum expectation value, which is odd under the orbifold symmetry and gives rise to the fermion bulk masses through non-universal Yukawa-like interactions. Like in the conventional Randall-Sundrum setup, the localization of the different fermion zero modes along the extra dimension naturally explains the observed flavor structure and four-dimensional mass hierarchy of the SM fermions. We study the phenomenological implications of the backreaction on the metric and the modified fermion profiles due to the bulk scalar field on electroweak precision and flavor observables. Using up-to-date data, we show that the contributions to the $S$, $T$, and ${ϵ}_K$ parameters require the mass of the first Kaluza-Klein gluon resonance to be of order 14 and 10 TeV in the minimal and the custodial model, respectively, regardless of the effect of the backreaction. Furthermore, effective flavor-changing interactions among the SM fermions induced by the bulk scalar are discussed. We also comment on the potential impact of the Higgs portal interaction of the bulk scalar on the couplings of the Higgs boson.

    hep-phJHEP(2019)·20 citations
12. 12*

    Misalignment & Co.: (Pseudo-)scalar and vector dark matter with curvature couplings

    Gonzalo Alonso Álvarez · Joerg Jaeckel🇩🇪 · Thomas Hugle🇩🇪

    Motivated by their potential role as dark matter, we study the cosmological evolution of light scalar and vector fields non-minimally coupled to gravity. Our focus is on a situation where the dominant contribution to the energy density arises from the misalignment mechanism. In addition, we also discuss the possibility that dark matter is generated in a stochastic scenario or from inflationary fluctuations. Even small deviations in the non-minimal couplings from the standard scenarios lead to significant qualitative and quantitative changes. This is due to the curvature-coupling driven superhorizon evolution of the homogeneous field and the non-zero momentum modes during inflation. Both the relic density yield and the large-scale density fluctuations are affected. For the misalignment mechanism, this results in a weakening of the isocurvature constraints and opens up new viable regions of parameter space.

    hep-phastro-ph.COJCAP(2020)·99 citations
13. 13*

    Impact of Cross-Sectional Uncertainties on DUNE Sensitivity due to Nuclear Effects

    Srishti Nagu🇮🇳 · Jaydip Singh🇮🇳 · Jyotsna Singh🇮🇳 · R.B. Singh🇮🇳

    In neutrino oscillation experiments precise measurement of neutrino oscillation parameters is of prime importance as well as a challenge. To improve the statistics, presently running and proposed experiments are using heavy nuclear targets. These targets introduce nuclear effects and the quantification of these effects on neutrino oscillation parameters will be decisive in the prediction of neutrino oscillation physics. Limited understanding of neutrino nucleus interactions and inaccurate reconstruction of neutrino energy causes uncertainty in the cross section. The error in the determination of cross section which contributes to systematic error introduces error in the neutrino mixing parameters that are determined by these experiments. In this work we focus on the variation in the predictions of DUNE potential, arising due to systematic uncertainties, using two different event generators-GENIE and GiBUU. These generators have different and independent cross-section models. To check the DUNE potential with the two generators as mentioned we have checked the senstivity studies of DUNE for CP violation, mass hierarchy and octant degeneracy.

    hep-phNPB(2020)·23 citations
14. 14*

    Light quark vacuum polarization at the physical point and contribution to the muon $g-2$

    Christopher Aubin🇺🇸 · Thomas Blum🇺🇸 · Cheng Tu🇺🇸 · Maarten Golterman🇺🇸 · Chulwoo Jung🇺🇸 · Santiago Peris🇪🇸

    We report on the computation of the connected light quark vacuum polarization with 2+1+1 flavors of HISQ fermions at the physical point and its contribution to the muon anomalous magnetic moment. Three ensembles, generated by the MILC collaboration, are used to take the continuum limit. The finite volume correction to this result is computed in the (Euclidean) time-momentum representation to NNLO in chiral perturbation theory. We find $a_{\mu }^{ll}(\mathrm{HVP})=(659\pm 20\pm 5\pm 5\pm 4)\times 10^{-10}$, where the errors are statistical and estimates of residual uncertainties from taking the continuum limit, scale setting, and truncation of chiral perturbation theory at NNLO. We compare our results with recent ones in the literature.

    ↳ hep-lathep-phPRD(2020)·159 citations
15. 15*

    Effect of the spatial curvature of the Universe on the form of the gravitational potential

    Maxim Eingorn🇺🇸 · A. Emrah Yukselci🇹🇷 · Alexander Zhuk🇹🇷

    Within the cosmic screening approach, we obtain the exact formulas for the velocity-independent gravitational potentials produced by matter in the form of discrete sources distributed in the open and closed Universes. These formulas demonstrate that spatial curvature of the Universe considerably affect the form of the potentials and forces. While in the open Universe the gravitational force undergoes exponential suppression at cosmological distances, in the closed Universe the force induced by an individual mass is equal to zero at the antipodal point with respect to this mass. The derived formulas are applicable for investigations of the motion of astrophysical objects (e.g., galaxies) in the open and closed Universes, and for simulations of the large scale structure formation.

    ↳ gr-qcastro-ph.COhep-phhep-thEPJC(2019)·13 citations
16. 16*

    The Schwinger Point

    Howard Georgi🇺🇸

    The Sommerfield model with a massive vector field coupled to a massless fermion in 1+1 dimensions is an exactly solvable analog of a Bank-Zaks model. The `physics' of the model comprises a massive boson and an unparticle sector that survives at low energy as a conformal field theory (Thirring model). I discuss the `Schwinger point' of the Sommerfield model in which the vector boson mass goes to zero. The limit is singular but gauge invariant quantities should be well-defined. I give a number of examples, both (trivially) with local operators and with nonlocal products connected by Wilson lines (the primary technical accomplishment in this note is the explicit and very pedestrian calculation of correlators involving straight Wilson lines). I hope that this may give some insight into the nature of bosonization in the Schwinger model and its connection with unparticle physics which in this simple case may be thought of as `incomplete bosonization.'

    ↳ hep-thhep-phJHEP(2019)·7 citations
17. 17*

    Hadron Spectroscopy and Resonances: Review

    M. Padmanath🇩🇪

    I review recent results on hadron spectroscopy using lattice QCD. In light of the discoveries in heavy baryon sector at LHCb over the past few years, lattice calculations in this regard are emphasized. Investigations on light baryon, heavy-heavy and heavy-light meson resonances are also discussed.

    ↳ hep-lathep-exhep-phPoS(2018)·30 citations
18. 18*

    Shower it again, Pythia

    Riccardo Di Sipio

    The Parton-Shower algorithm implement in the Pythia generator is applied multiple times to the same parton-level configuration to estimate the systematic uncertainty affecting large-radius jet substructure variables associated with the stochastic nature of the algorithm. Results are presented in the case of boosted $h\to b\bar{b}$ and $t\to bqq$. The code is publicly available on the repository https://github.com/rdisipio/ReShower.git

    ↳ hep-exhep-phPhys.Open(2019)·1 citation
19. 19*

    Full O(a) improvement in EQCD

    Guy D. Moore🇩🇪 · Niels Schlusser🇩🇪

    EQCD is a 3D bosonic theory containing SU(3) and an adjoint scalar, which efficiently describes the infrared, nonperturbative sector of hot QCD and which is highly amenable to lattice study. We improve the matching between lattice and continuum EQCD by determining the final unknown coefficient in the O(a) matching, an additive scalar mass renormalization. We do this numerically by using the symmetry-breaking phase transition point of the theory as a line of constant physics. This prepares the ground for a precision study of the transverse momentum diffusion coefficient C(qperp) within this theory. As a byproduct, we provide an updated version of the EQCD phase diagram.

    ↳ hep-lathep-phPRD(2019)·18 citations
20. 20*

    Coulomb final state interaction in heavy ion collisions for Levy sources

    Mate Csanad🇭🇺 · Sandor Lokos🇭🇺 · Marton I. Nagy🇭🇺

    Investigation of momentum space correlations of particles produced in high energy reactions requires taking final state interactions into account, a crucial point of any such analysis. Coulomb interaction between charged particles is the most important such effect. In small systems like those created in e+e- or p+p collisions, the so-called Gamow factor (valid for a point-like particle source) gives an acceptable description of the Coulomb interaction. However, in larger systems such as central or mid-central heavy ion collisions, more involved approaches are needed. In this paper we investigate the Coulomb final state interaction for Levy-type source functions that were recently shown to be of much interest for a refined description of the space-time picture of particle production in heavy-ion collisions.

    ↳ nucl-thhep-phUniverse(2019)·14 citations
21. 21*

    Charmed hadron production in an improved quark coalescence model

    Sungtae Cho🇰🇷 · Kai-Jia Sun🇺🇸 · Che Ming Ko🇺🇸 · Su Houng Lee🇰🇷 · Yongseok Oh🇰🇷

    We study the production of charmed hadrons $D^0$ and ${\Lambda }_c^{+}$ in relativistic heavy-ion collisions using an improved quark coalescence model. In particular, we extend the usual coalescence model by letting a produced hadron to have the same velocity as the center-of-mass velocity of coalesced constituent quarks during hadronization to take into account the effect of collective flow in produced quark-gluon plasma. This results in a shift of charmed resonances of higher masses to larger transverse momenta ($p_T^{}$). Requiring all charm quarks of very low $p_T^{}$ to be converted to hadrons via coalescence and letting charm quarks not undergoing coalescence to hadronize by independent fragmentation, we obtain a good description of the measured yield ratio ${\Lambda }_c^{+}/D^0$ as a function of $p_T^{}$ in $\text{Au}+\text{Au}$ collisions at ${\sqrt{s_{NN}}}^{}=200$~GeV by the STAR Collaboration at the Relativistic Heavy Ion Collider.

    ↳ nucl-thhep-phPRC(2020)·58 citations
22. 22*

    Unraveling the origin of black holes from effective spin measurements with LIGO-Virgo

    Nicolas Fernandez🇺🇸 · Stefano Profumo🇺🇸

    We investigate how to use information on the effective spin parameter of binary black hole mergers from the LIGO-Virgo gravitational wave detections to discriminate the origin of the merging black holes. We calculate the expected probability distribution function for the effective spin parameter for primordial black holes. Using LIGO-Virgo observations, we then calculate odds ratios for different models for the distribution of black holes' spin magnitude and alignment. We evaluate the posterior probability density for a possible mixture of astrophysical and primordial black holes as emerging from current data, and calculate the number of future merger events needed to discriminate different spin and alignment models at a given level of statistical significance.

    ↳ astro-ph.HEastro-ph.COgr-qchep-phJCAP(2019)·66 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.