Wed·Jan 16, 2019Wednesday·January 16, 2019

1. 01*

   Total Hadronic Cross Sections via the Holographic Pomeron Exchange

   Akira Watanabe🇨🇳

   The analysis on the hadron-hadron scattering at high energies in the framework of holographic QCD is presented. Combining the Pomeron exchange kernel and the hadron-Pomeron couplings which are obtained from the bottom-up AdS/QCD models, we calculate the total cross sections. Our calculation for the nucleon-nucleon scattering is consistent with the experimental data including the recent ones measured by the TOTEM collaboration at the LHC. Within the framework, one can consider other processes involving other hadrons. As examples to show this feature of the model, the resulting total cross sections of the pion-nucleon and pion-pion scattering are also presented.

   hep-phnucl-thJPS Conf.Proc.(2019)·0 citations
2. 02*

   Collinear matching for Sivers function at next-to-leading order

   Ignazio Scimemi🇪🇸 · Andrey Tarasov🇺🇸 · Alexey Vladimirov🇩🇪

   We evaluate the light-cone operator product expansion for the unpolarized transverse momentum dependent (TMD) operator in the background-field technique up twist-3 inclusively. The next-to-leading order (NLO) matching coefficient for the Sivers function is derived. The method, as well as many details of the calculation, are presented.

   hep-phJHEP(2019)·65 citations
3. 03*

   Lepton Flavor Violation and Neutrino Masses from $A_5$ and CP in the Non-Universal MSSM

   M.L. López-Ibáñez🇮🇹 · Aurora Melis🇪🇸 · Davide Meloni🇮🇹 · Óscar Vives🇪🇸

   We analyze the phenomenological consequences of embedding a flavor symmetry based on the groups $A_5$ and CP in a supersymmetric framework. We concentrate on the leptonic sector, where two different residual symmetries are assumed to be conserved at LO for charged and neutral leptons. All possible realizations to generate neutrino masses at tree level are investigated. Sizable flavor violating effects in the charged lepton sector are unavoidable due to the non-universality of soft-breaking terms determined by the symmetry. We derive testable predictions for the neutrino spectrum, lepton mixing and flavor changing processes with non-trivial relations among observables.

   hep-phJHEP(2019)·8 citations
4. 04*

   Reactor neutrino oscillations as constraints on Effective Field Theory

   Adam Falkowski🇫🇷 · Martín González-Alonso🇨🇭 · Zahra Tabrizi🇧🇷

   We study constraints on the Standard Model Effective Field Theory (SMEFT) from neutrino oscillations in short-baseline reactor experiments. We calculate the survival probability of reactors antineutrinos at the leading order in the SMEFT expansion, that is including linear effects of dimension-6 operators. It is shown that, at this order, reactor experiments alone cannot probe charged-current contact interactions between leptons and quarks that are of the (pseudo)vector (V$\pm$A) or pseudo-scalar type. We also note that flavor-diagonal (pseudo)vector coefficients do not have observable effects in oscillation experiments. In this we reach novel or different conclusions than prior analyses of non-standard neutrino interactions. On the other hand, reactor experiments offer a unique opportunity to probe tensor and scalar SMEFT operators that are off-diagonal in the lepton-flavor space. We derive constraints on the corresponding SMEFT parameters using the most recent data from the Daya Bay and RENO experiments.

   hep-phhep-exJHEP(2019)·57 citations
5. 05*

   Limiting Top-Higgs Interaction and Higgs-Boson Width from Multi-Top Productions

   Qing-Hong Cao🇨🇳 · Shao-Long Chen🇨🇳 · Yandong Liu🇨🇳 · Rui Zhang🇨🇳 · Ya Zhang🇨🇳

   We demonstrate that the multi-top productions efficiently probe the CP-property of top-Higgs interaction and the Higgs-boson width at the LHC. The four top-quark production alone can exclude a purely CP-odd top-quark Yukawa coupling at the 13~TeV LHC with an integrated luminosity of $430{\mathrm{fb}}^{-1}$, regardless the size of the Yukawa coupling. Combining the single Higgs-boson production, the $t\bar{t}H$ associated production and the four top-quark production, we show that the CP-phase of the top-quark Yukawa coupling and the Higgs-boson width can be stringently bounded at the LHC with integrated luminosities of $300{\mathrm{fb}}^{-1}$ and $3000{\mathrm{fb}}^{-1}$.

   hep-phhep-exPRD(2019)·63 citations
6. 06*

   Probing the transport properties of Quark-Gluon Plasma via heavy-flavor Boltzmann and Langevin dynamics

   Shuang Li🇨🇳 · Chaowen Wang🇨🇳 · Renzhuo Wan🇨🇳 · Jinfeng Liao🇺🇸

   The heavy quark propagation behavior inside the quark-gluon plasma (QGP), is usually described in terms of the Boltzmann dynamics, which can be reduced to the Langevin approach by assuming a small momentum transfer for the scattering processes between heavy quarks and the QGP constituents. In this work, the temperature and energy dependence of the transport coefficients are calculated in the framework of both Boltzmann and Langevin dynamics. The derived transport coefficients are found to be systematically larger in the Boltzmann approach as compared with the Langevin, in particular in the high temperature and high energy region. Within each of the two theoretical frameworks, we simulate the charm quark production and the subsequent evolution processes in relativistic heavy-ion collisions. We find that the total in-medium energy loss is larger from the Langevin dynamics, resulting in a smaller (larger) $R_{\mathrm{AA}}$ at high (low) $p_{\mathrm{T}}$, for both the charm quark and heavy-flavor mesons. Meanwhile, the Boltzmann model is found to induce larger $v_2$, in particular at moderate $p_{\mathrm{T}}$, as well as stronger broadening behavior for the azimuthal distributions. By comparing the model calculations with available experimental measurements for D-mesons, we find that the Langevin approach is more favored by the $R_{\mathrm{AA}}$ data while the Boltzmann approach is more favored favor by the $v_2$ data. A simultaneous description of both observables appear challenging for both models.

   hep-phPRC(2019)·33 citations
7. 07*

   What can We Learn from Triple Top-Quark Production?

   Qing-Hong Cao🇨🇳 · Shao-Long Chen🇨🇳 · Yandong Liu🇨🇳 · Xiao-Ping Wang🇺🇸

   Different from other multiple top-quark productions, triple top-quark production requires the presence of both flavor violating neutral interaction and flavor conserving neutral interaction. We describe the interaction of triple top-quarks and up-quark in terms of two dimension-6 operators; one can be induced by a new heavy vector resonance, the other by a scalar resonance. Combining same-sign top-quark pair production and four top-quark production, we explore the potential of the 13 TeV LHC on searching for the triple top-quark production.

   hep-phhep-exPRD(2019)·18 citations
8. 08*

   Renormalons and the Top Quark Mass Measurement

   Paolo Nason🇮🇹

   I illustrate a recent work on the large-order behaviour of the perturbative expansion (and the related power-suppressed ambiguities) arising from infrared renormalons, in the context of top mass measurements in open-top production processes.

   hep-phhep-ex3 citations
9. 09*

   Sensitivity to sterile neutrino mixing using reactor antineutrinos

   S. P. Behera🇮🇳 · D. K. Mishra🇮🇳 · L. M. Pant🇮🇳

   The reactor antineutrinos are used for the precise measurement of oscillation parameters in the 3-neutrino model, and also used to investigate active-sterile neutrino mixing sensitivity in the 3$+$1 neutrino framework. In the present work, we study the feasibility of sterile neutrino search with the Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experimental set-up using electron antineutrinos (${\overline{\nu }}_e$) produced from reactor as a source. The so-called 3$+$1 scenario is considered for active-sterile neutrino mixing, which leads to projected exclusion curves in the sterile neutrino mass and mixing angle plane. The analysis is performed considering both the reactor and detector related parameters. It is found that, the ISMRAN set-up can observe the active-sterile neutrino mixing sensitivity for ${\sin }^{2}2{\theta }_{14}\ge$ 0.064 and $\Delta m_{41}^2$ = 1.0 eV${}^2$ at 90$\%$ confidence level for an exposure of 1 ton-year by using neutrinos produced from the DHRUVA reactor with thermal power of 100 MW${}_{th}$. It is also observed that, there is a significant improvement of the active-sterile neutrino mixing parameter ${\sin }^{2}2{\theta }_{14}$ to $\sim$ 0.03 at the same $\Delta m_{41}^2$ by putting the ISMRAN detector set-up at a distance of 20 m from the compact proto-type fast breeder reactor (PFBR) facility with thermal power of 1250 MW${}_{th}$.

   hep-phnucl-exnucl-thEPJC(2019)·8 citations
10. 10*

    Scalar dark matter behind $b\to s\mu \mu$ anomaly

    Seungwon Baek🇰🇷

    We construct a scalar dark matter model with $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry in which the dark matter interacts with the quark flavours, allowing lepton non-universal $b\to s\ell \bar{\ell }$ decays. The model can solve $b\to s\mu \mu$ ($R_{K^{(\ast )}}$) anomaly and accommodate the relic abundance of dark matter simultaneously while satisfying the constraints from other low energy flavour experiments and direct detection experiments of dark matter. The new fields include vector-like heavy quarks $U$ and $D$, $U(1{)}_{L_{\mu }-L_{\tau }}$ breaking scalar $S$, as well as the dark matter candidate $X_I$ and its heavy partner $X_R$. To explain both $b\to s\mu \mu$ anomaly and the dark matter, {\it i)} large mass difference between $X_R$ and $X_I$ is required, {\it ii)} electroweak scale dark matter and heavy quarks are favoured, {\it iii)} not only electroweak scale but $\mathcal{O}(10)$ TeV dark gauge boson $Z^{\prime }$ and $X_R$ are allowed.

    hep-phJHEP(2019)·23 citations
11. 11*

    Testing for observability of Higgs effective couplings in triphoton production at FCC-hh

    H. Denizli🇹🇷 · K. Y. Oyulmaz🇹🇷 · A. Senol🇹🇷

    We investigate the potential of the $pp\to \gamma \gamma \gamma$ process to probe CP-conserving and CP-violating dimension-six operators of Higgs-gauge boson interactions in a model-independent Standard Model effective field theory framework at the center of mass energy of 100 TeV which is designed for the Future Circular hadron-hadron Collider. Signal events assuming the existence of anomalous Higgs boson couplings at $H\gamma \gamma$ and $HZ\gamma$ vertices and the relevant SM background events are generated in MadGraph, then passed through Pythia 8 for parton showering and Delphes to include detector effects. After detailed examination of kinematic variables, we use the invariant mass distribution of the two leading photons with optimized kinematic cuts to obtain constraints on the Wilson coefficients of dimension-six operators. We report that limits at 95\% confidence level on ${\bar{c}}_{\gamma }$ and ${\tilde{c}}_{\gamma }$ couplings with an integrated luminosity of 10 ab${}^{-1}$ are [-0.0051; 0.0038] and [-0.0043; 0.0043] without systematic error, respectively.

    hep-phJ.Phys.G(2019)·10 citations
12. 12*

    Light tetraquark state candidates

    Zhi-Gang Wang🇨🇳

    In this article, we study the axialvector-diquark-axialvector-antidiquark type scalar, axialvector, tensor and vector $ss\bar{s}\bar{s}$ tetraquark states with the QCD sum rules. The predicted mass $m_X=2.08\pm 0.12\mathrm{GeV}$ for the axialvector tetraquark state is in excellent agreement with the experimental value $(2062.8\pm 13.1\pm 4.2)\mathrm{MeV}$ from the BESIII collaboration and supports assigning the new $X$ state to be a $ss\bar{s}\bar{s}$ tetraquark state with $J^{PC}=1^{+-}$. The predicted mass $m_X=3.08\pm 0.11\mathrm{GeV}$ disfavors assigning the $\varphi (2170)$ or $Y(2175)$ to be the vector partner of the new $X$ state. As a byproduct, we obtain the masses of the corresponding $qq\bar{q}\bar{q}$ tetraquark states. The light tetraquark states lie in the region about $2\mathrm{GeV}$ rather than $1\mathrm{GeV}$.

    hep-phAdv.High Energy Phys.(2020)·25 citations
13. 13*

    Precision diboson measurements at hadron colliders

    A. Azatov🇮🇹 · D. Barducci🇮🇹 · E. Venturini🇮🇹

    We discuss the measurements of the anomalous triple gauge couplings at Large Hadron Collider focusing on the contribution of the ${\mathcal{O}}_{3W}$ and ${\mathcal{O}}_{3\tilde{W}}$ operators. These deviations were known to be particularly hard to measure due to their suppressed interference with the SM amplitudes in the inclusive processes, leading to approximate flat directions in the space of these Wilson coefficients. We present the prospects for the measurements of these interactions at HL-LHC and HE-LHC using exclusive variables sensitive to the interference terms and taking carefully into account effects appearing due to NLO QCD corrections.

    hep-phJHEP(2019)·65 citations
14. 14*

    In-medium properties of the low-lying bottom baryons in the quark-meson coupling model

    K. Tsushima🇧🇷

    In-medium properties of the low-lying baryons are studied in the quark-meson coupling (QMC) model, focusing on the ${\Sigma }_b$ and ${\Xi }_b$ baryons. It is predicted that the Lorentz-scalar effective mass of ${\Sigma }_b$ becomes smaller than that of ${\Xi }_b$ at moderate nuclear matter density, and as the density increases, namely, $m_{{\Sigma }_b}^{\ast }<m_{{\Xi }_b}^{\ast }$, although in vacuum $m_{{\Sigma }_b}>m_{{\Xi }_b}$. We also study the effects of the repulsive Lorentz-vector potentials on the excitation energies of these bottom baryons.

    hep-phnucl-thJPS Conf.Proc.(2019)·0 citations
15. 15*

    Study of the ${\Lambda }_b\to N^{\ast }{\ell }^{+}{\ell }^{-}$ decay in light cone sum rules

    T. M. Aliev (1)🇹🇷 · T. Barakat (2)🇸🇦 · M. Savci (3) ((1,3) Middle East Technical University/Ankara/Turkey, (2) King Saud University/Riyadh/Saudi Arabia)

    The form factors of the ${\Lambda }_b\to N^{\ast }{\ell }^{+}{\ell }^{-}$ decay are calculated in the framework of the light cone QCD sum rules. In the calculations the contribution of the negative parity ${\Lambda }_b^{\ast }$ baryon is eliminated by constructing the sum rules for different Lorentz structures. Furthermore the branching ratio of the semileptonic ${\Lambda }_b\to N^{\ast }{\ell }^{+}{\ell }^{-}$ decay is calculated. The numerical study for the branching ratio of the ${\Lambda }_b\to N^{\ast }{\ell }^{+}{\ell }^{-}$ decay indicates that it is quite large and could be measurable at future planned experiments to be conducted at LHCb.

    hep-phEPJC(2019)·3 citations
16. 16*

    Modelling and tuning in top quark physics

    Marek Schönherr🇨🇭

    In this proceedings I discuss the general strategy and impact of tuning Monte-Carlo event generators for physics processes involving top quarks. Special emphasis is put on disinguishing the different usages of event generators in the experiments and the subsequent implications on the tuning process. The current status of determining tune uncertainties is also discussed.

    hep-phhep-ex0 citations
17. 17*

    Near-the-origin divergence of Dirac wave functions of hydrogen and operator product expansion

    Yingsheng Huang🇨🇳 · Yu Jia🇨🇳 · Rui Yu🇨🇳

    There is a long-standing puzzle concerning the Coulomb solutions of the Dirac equation, i.e., what is the physics governing the weakly divergent near-the-origin behavior of the Dirac wave functions of the $n{S}_{1/2}$ hydrogen? As a sequel of our preceding work that aim to demystifying the universal near-the-origin behavior of the atomic Schrödinger and Klein-Gordon wave functions, the goal of this work is to demonstrate that, within the nonrelativistic effective field theory (NREFT) tailored for Coulombic atoms, the universal logarithmic divergence of the Dirac wave functions can be accounted by the perturbatively calculable Wilson coefficient emerging from the operator product expansion (OPE) of the electron and the nucleus fields. The cause is due to the relativistic kinetic correction and Darwin (zitterbewegung) term in the NREFT. With the aid of renormalization group equation, one can resum the leading logarithms to all orders in $Z\alpha$ and recover the $r^{-Z^2{\alpha }^2/2}$ anomalous scaling behavior exhibited by the Dirac wave function for the $n{S}_{1/2}$ hydrogen. It appears somewhat counterintuitive that these universal logarithmic divergences can not be accounted by the OPE set up in the relativistic QED. We are thereby enforced to conclude that the Dirac wave function must cease to be meaningful when $r$ is shorter than the electron's Compton wavelength.

    hep-phhep-thnucl-thphysics.atom-ph1 citation
18. 18*

    Is Higgsium a possibility in 2HDMs?

    Ambalika Biswas🇮🇳

    We investigate the possibility of a Higgs-Higgs bound state in the two Higgs doublet model. Specifically we look for the effect of dimension six operators, generated by new physics at a scale of a few TeV, on the self-couplings of the heavy CP even scalar field in the model. Following the pioneering work of Grinstein and Trott, we construct an effective field theory formalism to examine the physics of the Higgs sector. The magnitudes of the attractive and repulsive coupling strengths are compared to estimate the possibility of the formation of the $H-H$ bound state. Another way to check if a bound state is formed or not is from the formation and decay times of the bound state. The possibilities in various types of two Higgs doublet models have been discussed elaborately in the paper.

    hep-phNPB(2020)·3 citations
19. 19*

    Rare B, D and K decays, radiative and electroweak penguin decays, including constraints on $V_{td}/V_{ts}$ and ${ϵ}^{\prime }/ϵ$: Summary of CKM 2018 working group 3

    Michel De Cian🇨🇭 · Sébastien Descotes-Genon🇫🇷 · Karim Massri🇨🇭

    Rare $B$, $D$ and $K$ decays provide interesting probes of the Standard Model (SM), with a potential sensitivity to New Physics (NP) higher than other, more common, decays. Their experimental measurement is challenging, and their theoretical interpretation requires a precise knowledge of QCD at low energies, in the non-perturbative (hadronic) regime. The various $b$, $c$, $s$ decays provide different types of tests of the Standard Model, which can be performed in different experimental settings and which may exhibit correlated deviations in models of New Physics.

    ↳ hep-exhep-ph0 citations
20. 20*

    de Sitter versus Anti de Sitter flows and the (super)gravity landscape

    Elias Kiritsis🇬🇷 · Alexander Tsouros🇬🇷

    Generic solutions are studied in Einstein-scalar gravity in an ansatz that can interpolate between de Sitter and Anti-de Sitter regimes. The classification of regular solutions of \cite{exotic} is first extended to the dS regime. This implies, among others, the existence of cosmic clocks that reverse direction without passing through a curvature singularity. We then consider an ansatz for solutions that interpolate between the dS and AdS regimes. The structure of such more general solutions and their singularities are studied. It is shown that there are no regular solutions that interpolate between dS and AdS extrema for generic potentials. This is unlike the Centaur solutions that were shown to exist in two bulk dimensions. We also comment on the potential interplay with recent dS conjectures and the dS BF bounds.

    ↳ hep-thgr-qchep-phJHEP(2023)·18 citations
21. 21*

    Thermal corrections to quantum friction and decoherence: a Closed-Time-Path approach to atom-surface interaction

    Ludmila Viotti🇦🇷 · M. Belén Farías🇦🇷 · Paula I. Villar🇦🇷 · Fernando C. Lombardo🇦🇷

    In this paper we study the dissipative effects and decoherence induced on a particle moving at constant speed in front of a dielectric plate in quantum vacuum, developing a Closed-Time-Path (CTP) integral formulation in order to account for the corrections to these phenomena generated by finite temperatures. We compute the frictional force of the moving particle and find that it contains two different contributions: a pure quantum term due to quantum fluctuations (even present at vanishing temperatures) and a temperature dependent component generated by thermal fluctuations (bigger contribution the higher the temperature). We further estimate the decoherence timescale for the internal degree of freedom of the quantum particle. As expected, decoherence time is reduced by temperature, however, this feature is stronger for large velocities and for resonant situations. When the particle approaches relativistic speed, decoherence time becomes independent of temperature. The finite temperatures corrections to the force or even in the decoherence timescale could be used to track traces of quantum friction through the study of the velocity dependence since the solely evidence of this dependence provides an indirect testimony of the existence of a quantum frictional force

    ↳ quant-phcond-mat.otherhep-phPRD(2019)·15 citations
22. 22*

    Einstein Yang-Mills Higgs dark energy revisited

    Miguel Alvarez (1)🇨🇴 · J. Bayron Orjuela-Quintana (2)🇨🇴 · Yeinzon Rodriguez (1,3,4)🇨🇴 · Cesar A. Valenzuela-Toledo (2) ((1) Universidad Industrial de Santander, (2) Universidad del Valle, (3) Universidad Antonio Narino, (4) The Abdus Salam International Centre for Theoretical Physics)🇨🇴

    Inspired in the Standard Model of Elementary Particles, the Einstein Yang-Mills Higgs action with the Higgs field in the SU(2) representation was proposed in Class. Quantum Grav. 32 (2015) 045002 as the element responsible for the dark energy phenomenon. We revisit this action emphasizing in a very important aspect not sufficiently explored in the original work and that substantially changes its conclusions. This aspect is the role that the Yang-Mills Higgs interaction plays at fixing the gauge for the Higgs field, in order to sustain a homogeneous and isotropic background, and at driving the late accelerated expansion of the Universe by moving the Higgs field away of the minimum of its potential and holding it towards an asymptotic finite value. We analyse the dynamical behaviour of this system and supplement this analysis with a numerical solution whose initial conditions are in agreement with the current observed values for the density parameters. This scenario represents a step towards a successful merging of cosmology and well-tested particle physics phenomenology.

    ↳ gr-qcastro-ph.COhep-phClass.Quant.Grav.(2019)·33 citations
23. 23*

    Chiral vortices and pseudoscalar condensation due to rotation

    Lingxiao Wang🇨🇳 · Yin Jiang🇨🇳 · Lianyi He🇨🇳 · Pengfei Zhuang🇨🇳

    We investigate the influence of rotation on the dynamical chiral symmetry breaking in strongly interacting matter. We develop a self-consistent Bogoliubov-de Gennes-like theoretical framework to study the inhomogeneous chiral condensate and the possible chiral vortex state in rotating finite-size matter in four-fermion interacting theories. We show that for sufficiently rapid rotation in $2+1$ dimensions, the ground state can be a chiral vortex state, a type of topological defect in analogy to superfluids and superconductors. The vortex state exhibits pion condensation, providing a new mechanism to realize pseudoscalar condensation in strongly interacting matter.

    ↳ nucl-thcond-mat.quant-gascond-mat.supr-conhep-phPRD(2019)·22 citations
24. 24*

    Quantum scale symmetry

    C. Wetterich🇩🇪

    Quantum scale symmetry is the realization of scale invariance in a quantum field theory. No parameters with dimension of length or mass are present in the quantum effective action. Quantum scale symmetry is generated by quantum fluctuations via the presence of fixed points for running couplings. As for any global symmetry, the ground state or cosmological state may be scale invariant or not. Spontaneous breaking of scale symmetry leads to massive particles and predicts a massless Goldstone boson. A massless particle spectrum follows from scale symmetry of the effective action only if the ground state is scale symmetric. Approximate scale symmetry close to a fixed point leads to important predictions for observations in various areas of fundamental physics. We review consequences of scale symmetry for particle physics, quantum gravity and cosmology. For particle physics, scale symmetry is closely linked to the tiny ratio between the Fermi scale of weak interactions and the Planck scale for gravity. For quantum gravity, scale symmetry is associated to the ultraviolet fixed point which allows for a non-perturbatively renormalizable quantum field theory for all known interactions. The interplay between gravity and particle physics at this fixed point permits to predict couplings of the standard model or other "effective low energy models" for momenta below the Planck mass. In particular, quantum gravity determines the ratio of Higgs boson mass and top quark mass. In cosmology, approximate scale symmetry explains the almost scale-invariant primordial fluctuation spectrum which is at the origin of all structures in the universe. The pseudo-Goldstone boson of spontaneously broken approximate scale symmetry may be responsible for dynamical dark energy and a solution of the cosmological constant problem.

    ↳ hep-thastro-ph.COgr-qchep-ph134 citations
25. 25*

    Experimental prospects for $V_{ud}$, $V_{us}$, $V_{cd}$, $V_{cs}$ and (semi-)leptonic decays at LHCb

    Adam C. S. Davis (on behalf of the LHCb collaboration)🇬🇧

    We review the prospects of measurements of the CKM matrix elements corresponding to the first two generations of quarks, as well as measurements of leptonic and semileptonic charm meson decays at LHCb. We review the status of searches for Lepton Non-Universality in the charm sector, and provide motivation to continue such searches.

    ↳ hep-exhep-ph1 citation
26. 26*

    "Double-tracking" Characteristic of the Spectral Evolution of GRB 131231A: Synchrotron Origin?

    Liang Li🇨🇳 · Jin-Jun Geng🇨🇳 · Yan-Zhi Meng🇨🇳 · Xue-Feng Wu🇨🇳 · Yong-Feng Huang🇨🇳 · Yu Wang🇦🇲 · Rahim Moradi🇦🇲 · Z. Lucas Uhm🇺🇸 · Bing Zhang🇺🇸

    The characteristics of the spectral evolution of the prompt emission of gamma-ray bursts (GRBs), which are closely related to the radiation mechanism (synchrotron or photosphere), are still an unsolved subject. Here, by performing the detailed time-resolved spectral fitting of GRB 131231A, which has a very bright and well-defined single pulse, some interesting spectral evolution features have been found. (i) Both the low-energy spectral index $\alpha$ and the peak energy $E_{\mathrm{p}}$ exhibit the "flux-tracking" pattern ("double-tracking" characteristics). (ii) The parameter relations, i.e., $F$ (the energy flux)-$\alpha$, $F$-$E_{\mathrm{p}}$, and $E_{\mathrm{p}}$-$\alpha$, along with the analogous Yonetoku $E_{\mathrm{p}}$-$L_{\gamma ,\mathrm{iso}}$ relation for the different time-resolved spectra, show strong monotonous (positive) correlations, both in the rising and the decaying phases. (iii) The values of $\alpha$ do not exceed the synchrotron limit ($\alpha$= -2/3) in all slices across the pulse, favoring the synchrotron origin. We argue that the one-zone synchrotron emission model with the emitter streaming away at a large distance from the central engine can explain all of these special spectral evolution characteristics.

    ↳ astro-ph.HEhep-ph35 citations
27. 27*

    $B_s\to D_s^{(\ast )}l\nu$ Form Factors with Heavy HISQ Quarks

    E. McLean🇬🇧 · C.T.H. Davies🇬🇧 · A.T. Lytle🇮🇹 · J. Koponen🇮🇹

    We present progress on an ongoing calculation of the $B_s\to D_s^{(\ast )}l\nu$ form factors calculated on the $n_f=2+1+1$ MILC ensembles and using the Highly Improved Staggered Quark action for all valence quarks. We perform the calculation at a range of $b$ quark masses (and lattice spacings) so that we can extrapolate to the physical $b$-quark mass.

    ↳ hep-lathep-phPoS(2019)·7 citations
28. 28*

    CKM 2018 Summary of Working Group 4: Mixing and mixing-related CP violation in the B system $\Delta M$, $\Delta \Gamma$, ${\varphi }_s$, ${\varphi }_1/\beta$, ${\varphi }_2/\alpha$, ${\varphi }_3/\gamma$

    Sevda Esen🇳🇱 · Alexander Lenz🇬🇧

    We summarise the excellent talks of Working group 4 at the 10th CKM Workshop in Heidelberg taking place from 17th till 21st September 2018.

    ↳ hep-exhep-ph4 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.