Thu·Oct 17, 2019Thursday·October 17, 2019

1. 01*

   DYTurbo: Fast predictions for Drell-Yan processes

   Stefano Camarda🇨🇭 · Maarten Boonekamp🇫🇷 · Giuseppe Bozzi🇮🇹 · Stefano Catani🇮🇹 · Leandro Cieri🇮🇹 · Jakub Cuth🇩🇪 · Giancarlo Ferrera🇮🇹 · Daniel de Florian🇦🇷 · Alexandre Glazov🇩🇪 · Massimiliano Grazzini🇨🇭 · Manuella G. Vincter🇨🇦 · Matthias Schott🇩🇪

   Drell-Yan lepton pair production processes are extremely important for Standard Model (SM) precision tests and for beyond the SM searches at hadron colliders. Fast and accurate predictions are essential to enable the best use of the precision measurements of these processes; they are used for parton density fits, for the extraction of fundamental parameters of the SM, and for the estimation of background processes in searches. This paper describes a new numerical program, DYTurbo, for the calculation of the QCD transverse-momentum resummation of Drell-Yan cross sections up to next-to-next-to-leading logarithmic accuracy combined with the fixed-order results at next-to-next-to-leading order ($\mathcal{O}({\alpha }_{\mathrm{S}}^2)$), including the full kinematical dependence of the decaying lepton pair with the corresponding spin correlations and the finite-width effects. The DYTurbo program is an improved reimplementation of the DYqT, DYqT and DYNNLO programs, which provides fast and numerically precise predictions through the factorisation of the cross section into production and decay variables, and the usage of quadrature rules based on interpolating functions for the integration over kinematic variables.

   hep-phEPJC(2020)·153 citations
2. 02*

   The effect of improved high-energy muon cross-sections

   Jan Soedingrekso🇩🇪 · Alexander Sandrock🇩🇪 · Wolfgang Rhode🇩🇪

   A precise simulation of muons with energies above a TeV is crucial for neutrino telescopes or cosmic ray experiments. To further increase the precision of these simulations, improved cross-section calculations are needed. At these energies, the interaction probability is dominated by bremsstrahlung for large energy losses and electron-positron pair production for small energy losses. Improved analytical calculations for these processes were developed with more precise screening functions of the target atom as well as higher order corrections reducing the systematic uncertainties below the percent level. The new calculations are already implemented in the new version of the lepton propagator PROPOSAL, which was designed to be highly performant for the propagation through large volumes of media using interpolation tables and to do systematic studies with its multiple available cross-section calculations. The new calculations of the differential cross-section result in a maximum deviation of 3 percent to the current standard. Their effects on the muon simulation with the resulting flux and energy loss distribution are presented.

   hep-phPoS(2020)·5 citations
3. 03*

   Neutrino Oscillations and Energy-Momentum Conservation

   HoSeong La🇺🇸

   It is proposed that the energy-momentum expectation values of flavor states should be identified with the missing energy-momentum of neutrino processes so that the conservation of energy-momentum can be strictly imposed. It is also observed that there is a plausible condition to express neutrino mixing angles in terms of neutrino masses without invoking symmetries.

   hep-phnucl-th0 citations
4. 04*

   Survival of heavy flavored mesons in a hot medium

   B.Z. Kopeliovich🇨🇱 · Jan Nemchik🇨🇿 · I.K. Potashnikova🇨🇱 · Ivan Schmidt🇨🇱

   Hadronization of heavy quarks reveals various unusual features. Gluon radiation by a heavy quark originated from a hard process, ceases shortly on a distance of the order of few fm. Due to the dead-cone effect a heavy quark radiates only a small fraction of its energy. This is why the measured fragmentation function D(z) peaks at large z. Hadronization finishes at very short distances, well shorter than 1 fm, by production of a colorless small-size Qq-bar dipole. This ensures dominance of a perturbative mechanism and makes possible factorization of short and long distances. The latter corresponds to final state interactions of the produced dipole propagating through a dense medium. The results provide good description of data on beauty and charm suppression in heavy ion collisions, fixing the transport coefficient for b-quarks about twice smaller than for charm, and both significantly lower that the values determined from data on suppression of high-pT light hadrons. We relate this to reduction of the QCD coupling at higher scales, and suppression of radiation by the dead-cone effect.

   hep-phnucl-th2 citations
5. 05*

   Production and constraints for a massive dark photon at electron-positron colliders

   Jun Jiang🇨🇳 · Chun-Yuan Li🇨🇳 · Shi-Yuan Li🇨🇳 · Shankar Dayal Pathak🇨🇳 · Zong-Guo Si🇨🇳 · Xing-Hua Yang🇨🇳

   Dark sector may couple to the Standard Model via one or more mediator particles. We discuss two types of mediators: the dark photon $A^{\prime }$ and the dark scalar mediator $\varphi$. The total cross-sections and various differential distributions of the processes $e^{+}{e}^{-}\to q\bar{q}{A}^{\prime }$ and $e^{+}{e}^{-}\to q\bar{q}\varphi$ ($q=u,d,c,s$ and $b$ quarks) are discussed. We focus on the study of the invisible $A^{\prime }$ due to the cleaner background at future $e^{+}{e}^{-}$ colliders. It is found that the kinematic distributions of the two-jet system could be used to identify (or exclude) the dark photon and the dark scalar mediator, as well as to distinguish between them. We further study the possibility of a search for dark photons at a future CEPC experiment with $\sqrt{s}=$ 91.2 GeV and 240 GeV. With CEPC running at $\sqrt{s}=$ 91.2 GeV, it would be possible to perform a decisive measurement of the dark photon (20 GeV $<m_{A^{\prime }}<$ 60 GeV) in less than one operating year. The lower limits of the integrated luminosity for the significance $S/\sqrt{B}=$ 2$\sigma$, 3$\sigma$ and 5$\sigma$ are presented.

   hep-phCPC(2020)·8 citations
6. 06*

   Neutrino masses in an $SU(4)\times U(1)$ -- electroweak model with a scalar decuplet

   N. Anh Ky🇻🇳 · N. T. Hong Van🇻🇳 · D. Nguyen Dinh🇻🇳 · P. Quang Van🇻🇳

   A neutrino mass model is suggested within an $SU(4)\times U(1)$ -- electroweak theory. The smallness of neutrino masses can be guaranteed by a seesaw mechanism realized through Yukawa couplings to a scalar $SU(4)$-decuplet. In this scheme the light active neutrinos are accompanied by heavy neutrinos, which may have masses at different scales, including those within eV-MeV scales investigated quite intensively in both particle physics and astrophysics/cosmology. The flavour neutrinos are superpositions of light neutrinos and a small fraction of heavy neutrinos with the mixing to be determined by the model's parameters (Yukawa coupling coefficients or symmetry breaking scales). The distribution shape of the Yukawa couplings can be visualized via a model-independent distribution of the neutrino mass matrix elements derived by using the current experimental data. With reference to several current and near future experiments, detectable bounds of these heavy neutrinos at different mass scales are discussed and estimated.

   hep-phEPJC(2019)·0 citations
7. 07*

   The electromagnetic form factors of the transition from the spin-3/2 Sigma to the Lambda hyperon

   Olov Junker🇸🇪 · Stefan Leupold🇸🇪 · Elisabetta Perotti🇸🇪 · Timea Vitos (Uppsala U.)🇸🇪

   The three electromagnetic form factors for the transition from a 3/2+ Sigma* hyperon to the ground-state Lambda hyperon are studied. At low energies, combinations of the transition form factors can be deduced from Dalitz decays of the Sigma* hyperon to Lambda plus an electron-positron pair. It is pointed out how more information can be obtained with the help of the self-analyzing weak decay of the Lambda. In particular it is shown that these transition form factors are complex quantities already in this kinematical region. Such measurements are feasible at hyperon factories as for instance the Facility for Antiproton and Ion Research (FAIR). At higher energies, the transition form factors can be measured in electron-positron collisions. The pertinent relations between the transition form factors and the decay distributions and differential cross sections are presented. Using dispersion theory, the low-energy electromagnetic form factors for the Sigma*-to-Lambda transition are related to the pion vector form factor. The additionally required input, i.e. the two-pion - Sigma* - Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and the decuplet. A poorly known NLO parameter is fixed to the experimental value of the Sigma* to Lambda-gamma decay width. Pion rescattering is taken into account by dispersion theory solving a Muskhelishvili-Omnes equation. Subtracted and unsubtracted dispersion relations are discussed. However, in view of the fact that the transition form factors are complex quantities, the current data situation does not allow for a full determination of the subtraction constants. To reduce the number of free parameters, unsubtracted dispersion relations are used to make predictions for the transition form factors in the low-energy space- and timelike regions.

   hep-phnucl-thPRC(2020)·25 citations
8. 08*

   Searching for supersymmetry and its avatars

   John Ellis🇬🇧

   {\it Why continue looking for supersymmetry?} Over and above the aesthetic and theoretical motivations from string theory, there are several longstanding phenomenological motivations for TeV-scale supersymmetry such as the electroweak scale, and the lightest supersymmetric particle (LSP) as cold dark matter. Run~1 of the LHC has actually provided three extra motivations, namely the stabilization of the electroweak vacuum, and successful predictions for the Higgs mass and couplings. {\it How to look for it?} There are several examples of emergent supersymmetry, the most recent being on the surfaces of topological insulators, and some sort of effective supersymmetry could be useful for boosting the power of laser arrays. At the LHC, attention is moving towards signatures that had previously been neglected, such as long-lived charged particles - which might be an opportunity for the MoEDAL experiment.

   hep-phhep-exPhil.Trans.Roy.Soc.Lond.A(2019)·7 citations
9. 09*

   Cutting massless four-loop propagators

   Vitaly Magerya🇩🇪 · Andrey Pikelner🇷🇺

   Among the unitarity cuts of 4-loop massless propagators two kinds are currently fully known: the 2-particle cuts with 3 loops corresponding to form-factors, and the 5-particle phase-space integrals. In this paper we calculate master integrals for the remaining ones: 3-particle cuts with 2 loops, and 4-particle cuts with 1 loop. The 4-particle cuts are calculated by solving dimensional recurrence relations. The 3-particle cuts are integrated directly using 1->3 amplitudes with 2 loops, which we also re-derive here up to transcendentality weight 7. The results are verified both numerically, and by showing consistency with previously known integrals using Cutkosky rules. We provide the analytic results in the space-time dimension 4-2{\epsilon} as series in {\epsilon} with coefficients being multiple zeta values up to weight 12. In the ancillary files we also provide dimensional recurrence matrices and SummerTime files suitable for numerical evaluation of the series in arbitrary dimensions with any precision.

   hep-phJHEP(2019)·19 citations
10. 10*

    Minimal Warm Inflation

    Kim V. Berghaus🇺🇸 · Peter W. Graham🇺🇸 · David E. Kaplan🇺🇸

    Slow-roll inflation is a successful paradigm. However we find that even a small coupling of the inflaton to other light fields can dramatically alter the dynamics and predictions of inflation. As an example, the inflaton can generically have an axion-like coupling to gauge bosons. Even relatively small couplings will automatically induce a thermal bath during inflation. The thermal friction from this bath can easily be stronger than Hubble friction, significantly altering the usual predictions of any particular inflaton potential. Thermal effects suppress the tensor-to-scalar ratio $r$ significantly, and predict unique non-gaussianities. This axion-like coupling provides a minimal model of warm inflation which avoids the usual problem of thermal backreaction on the inflaton potential. As a specific example, we find that hybrid inflation with this axion-like coupling can easily fit the current cosmological data.

    hep-phastro-ph.COhep-thJCAP(2020)·155 citations
11. 11*

    Exotic Lepton-Flavor Violating Higgs Decays

    Jared A. Evans🇺🇸 · Philip Tanedo🇺🇸 · Mohammadreza Zakeri🇨🇳

    Exotic Higgs decays are promising channels to discover new physics in the near future. We present a simple model with a new light scalar that couples to the Standard Model through a charged lepton-flavor violating interaction. This can yield exciting new signatures, such as $h\to e^{+}{e}^{+}{\mu }^{-}{\mu }^{-}$, that currently have no dedicated searches at the Large Hadron Collider. We discuss this model in detail, assess sensitivity from flavor constraints, explore current constraints from existing multi-lepton searches, and construct a new search strategy to optimally target these exotic, lepton-flavor violating Higgs decays.

    hep-phJHEP(2020)·11 citations
12. 12*

    A more attractive scheme for radion stabilization and supercooled phase transition

    Kohei Fujikura🇯🇵 · Yuichiro Nakai🇨🇳 · Masaki Yamada🇺🇸

    We propose a new radion stabilization mechanism in the Randall-Sundrum spacetime, introducing a bulk $SU(N_H)$ gauge field which confines at a TeV scale. It turns out that the radion is stabilized by the balance between a brane tension and a pressure due to the Casimir energy of the strong $SU(N_H)$ gauge field. We investigate the phase transition between the Randall-Sundrum (compactified) spacetime and a de-compactified spacetime and determine the parameter regime in which eternal (old) inflation is avoided and the phase transition can be completed. In comparison to the Goldberger-Wise mechanism, the 5D Planck mass can be larger than the AdS curvature and a classical description of the gravity is reliable in our stabilization mechanism. We also discuss the effect of the phase transition in cosmology such as an entropy dilution and a production of gravitational waves.

    hep-phastro-ph.COhep-thJHEP(2020)·60 citations
13. 13*

    Light-Cone Sum Rules Analysis of ${\Xi }_{Q{Q}^{\prime }}\to {\Sigma }_{Q^{\prime }}$ Weak Decays

    Xiao-Hui Hu🇨🇳 · Yu-Ji Shi🇩🇪

    As a continuation of our previous work, we investigate the weak decays of doubly-heavy baryons ${\Xi }_{Q{Q}^{\prime }}$ into sextet ${\Sigma }_{Q^{\prime }}$ with light-cone sum rules. We calculate the form factors for these decays with the parallel light-cone distribution amplitudes of ${\Sigma }_{Q^{\prime }}$. Numerical results of these form factors are used to predict the decay widths and branching ratios of the corresponding semi-leptonic processes. Parametric uncertainties and theoretical analyses are also given in detail. We find that the decay widths of ${\Xi }_{cc}$ and ${\Xi }_{bc}$ decays are several orders of magnitude larger than those of ${\Xi }_{bb}$ decays.

    hep-phEPJC(2020)·30 citations
14. 14*

    Parameter-free velocity-dependent one-scale model for domain walls

    P. P. Avelino🇵🇹

    We develop a parameter-free velocity-dependent one-scale model for the evolution of the characteristic length $L$ and root-mean-square velocity ${\sigma }_v$ of standard domain wall networks in homogeneous and isotropic cosmologies. We compare the frictionless scaling solutions predicted by our model, in the context of cosmological models having a power law evolution of the scale factor $a$ as a function of the cosmic time $t$ ($a\propto t^{\lambda }$, $0<\lambda <1$), with the corresponding results obtained using field theory numerical simulations. We show that they agree well (within a few $\%$) for root-mean-square velocities ${\sigma }_v$ smaller than $0.2c$ ($\lambda \ge 0.9$), where $c$ is the speed of light in vacuum, but significant discrepancies occur for larger values of ${\sigma }_v$ (smaller values of $\lambda$). We identify problems with the determination of $L$ and ${\sigma }_v$ from numerical field theory simulations which might potentially be responsible for these discrepancies.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2020)·12 citations
15. 15*

    Jet quenching in the hadron gas: an exploratory study

    Philipp Dorau🇩🇪 · Jean-Bernard Rose🇩🇪 · Daniel Pablos🇳🇴 · Hannah Elfner🇩🇪

    The suppression of high momentum particles in heavy-ion collisions in comparison to elementary reactions is one of the main indications for the formation of a quark-gluon plasma. In recent studies, full jets are being reconstructed and substructure observables are gaining importance in assessing the medium modifications of hard probes. In this work, the effect of the late stage hadronic interactions are explored within the hadronic transport approach SMASH (Simulating Many Accelerated Strongly-interacting Hadrons). High momentum particles are incorporated in a radially expanding hadron gas to analyse the corresponding angular distributions, also refered to as `jet shape' observables. We find that the full hadron gas can be approximated with a pion gas with constant elastic cross-sections of 100 mb. In addition, the temperature and probe energy dependence of diffusion coefficients $\tilde{q}$ and $\tilde{e}$ quantifying the transverse and parallel momentum transfers are extracted. The species dependence and the importance of different interaction types are investigated. Parametrizations are presented that can be employed in future jet quenching calculations to include the effect of the hadronic phase.

    ↳ nucl-thhep-phPRC(2020)·28 citations
16. 16*

    Exotic Charmonium at BESIII

    Ilaria Balossino🇮🇹

    The BESIII Experiment at the Beijing Electron Positron Collider (BEPCII) collected large data samples for electron-positron collisions with center-of-mass above 4 GeV. The analysis of these samples has resulted in a number of surprising discoveries, such as the discoveries of the electrically charged ${\mathrm{Z}}_{\mathrm{c}}$ structures, which, if resonant, cannot be accommodated in the traditional charm quark and anti-charm quark picture of charmonium. In this talk, we will review the current status of the analyses of the exotic states, as well as a number of other interesting features in the new BESIII data samples.

    ↳ hep-exhep-ph1 citation
17. 17*

    $\Delta$-mass dependence of the M-matrix in the calculation of $\text{mbox}N\Delta \to \text{mbox}NN$ cross sections

    Ying Cui🇨🇳 · Yingxun Zhang🇨🇳 · Zhuxia Li🇨🇳

    Within the one boson exchange model, $\Delta$-mass dependent M-matrix and its influence on the calculation of $N\Delta \to NN$ cross sections are investigated. Our calculations show that the $m_{\Delta }$ dependence of $|{\text{p}}_{N\Delta }|$ and $|\mathcal{M}{|}^2$ has effects on the calculations of ${\sigma }_{N\Delta \to NN}$, especially around the threshold energy. We finally provide a table of accurate ${\sigma }_{N\Delta \to NN}$ which can be used in the transport models.

    ↳ nucl-thhep-phCPC(2020)·8 citations
18. 18*

    Toward a robust inference method for the likelihood of low-luminosity gamma-ray bursts to be progenitors of ultrahigh-energy cosmic rays correlating with starburst galaxies

    Luis A. Anchordoqui🇺🇸 · Claire Mechmann🇺🇸 · Jorge F. Soriano🇺🇸

    Very recently, the Pierre Auger Collaboration reported a $4.5\sigma$ correlation between the arrival directions of the highest energy cosmic rays and nearby starburst galaxies. The cosmic rays producing the anisotropy signal have been proposed to originate in low-luminosity gamma-ray bursts (llGRBs). On the basis of the well-justified assumption that at redshift $z<0.3$ the host metallicity is a good indicator of the llGRB production rate, we show that the association of llGRBs and the starbursts correlating with Auger data is excluded at the 90% confidence level.

    ↳ astro-ph.HEhep-phJHEAp(2020)·6 citations
19. 19*

    Safe Hologram

    Borut Bajc🇸🇮 · Adrian Lugo🇦🇷 · Francesco Sannino🇩🇰

    We introduce a holographic model encapsulating the dynamics of safe quantum field theories.

    ↳ hep-thhep-phMod.Phys.Lett.A(2020)·1 citation
20. 20*

    Excited bottomonia in quark-gluon plasma from lattice QCD

    Rasmus Larsen🇺🇸 · Stefan Meinel🇺🇸 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸

    We present the first lattice QCD study of up to $3S$ and $2P$ bottomonia at non-zero temperatures. Correlation functions of bottomonia were computed using novel bottomonium operators and a variational technique, within the lattice non-relativistic QCD framework. We analyzed the bottomonium correlation functions based on simple physically-motivated spectral functions. We found evidence of sequential in-medium modifications, in accordance with the sizes of the bottomonium states.

    ↳ hep-lathep-phnucl-thPLB(2020)·78 citations
21. 21*

    Proceedings of The Magnificent CE$\nu$NS Workshop 2018

    D. Aristizabal Sierra🇨🇱 · A.B. Balantekin🇺🇸 · D. Caratelli🇺🇸 · B. Cogswell🇬🇧 · J.I. Collar🇺🇸 · C.E. Dahl🇺🇸 · J. Dent🇺🇸 · B. Dutta🇺🇸 · J. Engel🇺🇸 · J. Estrada🇺🇸 · J. Formaggio🇺🇸 · S. Gariazzo🇪🇸 and 33 other authors

    The Magnificent CE$\nu$NS Workshop (2018) was held November 2 & 3 of 2018 on the University of Chicago campus and brought together theorists, phenomenologists, and experimentalists working in numerous areas but sharing a common interest in the process of coherent elastic neutrino-nucleus scattering (CE$\nu$NS). This is a collection of abstract-like summaries of the talks given at the meeting, including links to the slides presented. This document and the slides from the meeting provide an overview of the field and a snapshot of the robust CE$\nu$NS-related efforts both planned and underway.

    ↳ hep-exastro-ph.IMhep-phnucl-ex+18 citations
22. 22*

    Deeply virtual Compton Scattering off ${}^4$He

    Sara Fucini🇮🇹 · Sergio Scopetta🇮🇹 · Michele Viviani🇮🇹

    Deeply virtual Compton scattering is a fascinating process which can provide a tomographic view of nuclei and bound nucleons. The first experimental results for ${}^4$He targets, recently released at Jefferson Lab, have been analyzed here in a rigorous Impulse Approximation scenario. For both the coherent and incoherent channels of the process, the main experimental observables have been written in terms of state-of-the-art models of the nuclear spectral function and of the parton structure of the bound proton. A good overall agreement with the data is obtained. The calculation shows that a comparison of our conventional results with future precise data can expose novel quark and gluon effects in nuclei.

    ↳ nucl-thhep-phJ.Phys.Conf.Ser.(2020)·0 citations
23. 23*

    The dark matter component of the Gaia radially anisotropic substructure

    Nassim Bozorgnia🇬🇧 · Azadeh Fattahi🇬🇧 · Carlos S. Frenk🇬🇧 · Andrew Cheek🇬🇧 · David G. Cerdeno🇬🇧 · Facundo A. Gómez🇨🇱 · Robert J. J. Grand🇩🇪 · Federico Marinacci🇮🇹

    We study the properties of the dark matter component of the radially anisotropic stellar population recently identified in the Gaia data, using magneto-hydrodynamical simulations of Milky Way-like halos from the Auriga project. We identify 10 simulated galaxies that approximately match the rotation curve and stellar mass of the Milky Way. Four of these have an anisotropic stellar population reminiscent of the Gaia structure. We find an anti-correlation between the dark matter mass fraction of this population in the Solar neighbourhood and its orbital anisotropy. We estimate the local dark matter density and velocity distribution for halos with and without the anisotropic stellar population, and use them to simulate the signals expected in future xenon and germanium direct detection experiments. We find that a generalized Maxwellian distribution fits the dark matter halo integrals of the Milky Way-like halos containing the radially anisotropic stellar population. For dark matter particle masses below approximately 10 GeV, direct detection exclusion limits for the simulated halos with the anisotropic stellar population show a mild shift towards smaller masses compared to the commonly adopted Standard Halo Model.

    ↳ astro-ph.GAastro-ph.COhep-phJCAP(2020)·51 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.