Fri·Jan 27, 2017Friday·January 27, 2017

1. 01*

   Mixed Higgs-Radion States at the LHC -- a Detailed Study

   Amit Chakraborty🇯🇵 · Ushoshi Maitra🇮🇳 · Sreerup Raychaudhuri🇮🇳 · Tousik Samui🇮🇳

   Light radions constitute one of the few surviving possibilities for observable new particle states at the sub-TeV level which arise in models with extra spacetime dimensions. It is already known that the 125 GeV state discovered at CERN is unlikely to be a pure radion state, since its decays resemble those of the Standard Model Higgs boson too closely. However, due to experimental errors in the measured decay widths, the possibility still remains that it could be a mixture of the radion with one (or more) Higgs states. We use the existing LHC data at 8 and 13 TeV to make a thorough investigation of this possibility. Not surprisingly, it turns out that this model is already constrained quite effectively by direct LHC searches for an additional scalar heavier than 125 GeV. We then make a detailed study of the so-called 'conformal point', where this heavy state practically decouples from (most of) the Standard Model fields. Some projections for the future are also included.

   hep-phhep-exNPB(2017)·19 citations
2. 02*

   Chiral dynamics, S-wave contributions and angular analysis in $D\to \pi \pi \ell \bar{\nu }$

   Yu-Ji Shi🇨🇳 · Wei Wang🇨🇳 · Shuai Zhao🇨🇳

   We present a theoretical analysis of the $D^{-}\to {\pi }^{+}{\pi }^{-}\ell \bar{\nu }$ and ${\bar{D}}^0\to {\pi }^{+}{\pi }^0\ell \bar{\nu }$ decays. We construct a general angular distribution which can include arbitrary partial waves of $\pi \pi$. Retaining the S-wave and P-wave contributions we study the branching ratios, forward--backward asymmetries and a few other observables. The P-wave contribution is dominated by ${\rho }^0$ resonance, and the S-wave contribution is analyzed using the unitarized chiral perturbation theory. The obtained branching fraction for $D\to \rho \ell \nu$, at the order $10^{-3}$, is consistent with the available experimental data. The S-wave contribution has a branching ratio at the order of $10^{-4}$, and this prediction can be tested by experiments like BESIII and LHCb. Future measurements can also be used to examine the $\pi$--$\pi$ scattering phase shift.

   hep-phhep-exEPJC(2017)·21 citations
3. 03*

   Precise predictions for charged Higgs boson production

   Maria Ubiali🇬🇧

   We review some of the major progress in the accurate calculation of the cross section for the production of a charged Higgs boson in a generic two-Higgs double model, by focussing on the high-mass region, for which new calculations have been made available in the past few years, both at the level of total and of differential cross sections. Furthermore, we illustrate some recent progress in the calculation of the total cross section for a charged Higgs boson with mass in the intermediate range m_{H^\pm} \sim m_{t}, including top-resonant contributions.

   hep-phPoS(2017)·0 citations
4. 04*

   Cornering Compressed Gluino at the LHC

   Natsumi Nagata🇯🇵 · Hidetoshi Otono🇯🇵 · Satoshi Shirai🇯🇵

   We discuss collider search strategies of gluinos which are highly degenerate with the lightest neutralino in mass. This scenario is fairly difficult to probe with conventional search strategies at colliders, and thus may provide a hideaway of supersymmetry. Moreover, such a high degeneracy plays an important role in dark matter physics as the relic abundance of the lightest neutralino is significantly reduced via coannihilation. In this paper, we discuss ways of uncovering this scenario with the help of longevity of gluinos; if the mass difference between the lightest neutralino and gluino is $\lesssim 100$ GeV and squarks are heavier than gluino, then the decay length of the gluino tends to be of the order of the detector-size scale. Such gluinos can be explored in the searches of displaced vertices, disappearing tracks, and anomalously large energy deposit by (meta)stable massive charged particles. We find that these searches are complementary to each other, and by combining their results we may probe a wide range of the compressed gluino region in the LHC experiments.

   hep-phJHEP(2017)·22 citations
5. 05*

   Higgs Scalaron Mixed Inflation

   Yohei Ema🇯🇵

   We discuss the inflationary dynamics of a system with a non-minimal coupling between the Higgs and the Ricci scalar as well as a Ricci scalar squared term. There are two scalar modes in this system, i.e. the Higgs and the spin-zero mode of the graviton, or the scalaron. We study the two-field dynamics of the Higgs and the scalaron during inflation, and clarify the condition where inflation is dominated by the Higgs/scalaron. We also find that the cut-off scale at around the vacuum is as large as the Planck scale, and hence there is no unitarity issue, although there is a constraint on the couplings from the perturbativity of the theory at around the vacuum.

   hep-phastro-ph.COPLB(2017)·161 citations
6. 06*

   Markov Chain Monte Carlo technics applied to Parton Distribution Functions determination: proof of concept

   Yémalin Gabin Gbedo🇫🇷 · Mariane Mangin-Brinet🇫🇷

   We present a new procedure to determine Parton Distribution Functions (PDFs), based on Markov Chain Monte Carlo (MCMC) methods. The aim of this paper is to show that we can replace the standard ${\chi }^2$ minimization by procedures grounded on Statistical Methods, and on Bayesian inference in particular, thus offering additional insight into the rich field of PDFs determination. After a basic introduction to these technics, we introduce the algorithm we have chosen to implement -- namely Hybrid (or Hamiltonian) Monte Carlo. This algorithm, initially developed for Lattice QCD, turns out to be very interesting when applied to PDFs determination by global analyses; we show that it allows to circumvent the difficulties due to the high dimensionality of the problem, in particular concerning the acceptance. A first feasibility study is performed and presented, which indicates that Markov Chain Monte Carlo can successfully be applied to the extraction of PDFs and of their uncertainties.

   hep-phPRD(2017)·13 citations
7. 07*

   Emergent Supersymmetry in Local Equilibrium Systems

   Ping Gao🇺🇸 · Hong Liu🇺🇸

   Many physical processes we observe in nature involve variations of macroscopic quantities over spatial and temporal scales much larger than microscopic molecular collision scales and can be considered as in local thermal equilibrium. In this paper we show that any classical statistical system in local thermal equilibrium has an emergent supersymmetry at low energies. We use the framework of non-equilibrium effective field theory for quantum many-body systems defined on a closed time path contour and consider its classical limit. Unitarity of time evolution requires introducing anti-commuting degrees of freedom and BRST symmetry which survive in the classical limit. The local equilibrium is realized through a $Z_2$ dynamical KMS symmetry. We show that supersymmetry is equivalent to the combination of BRST and a specific consequence of the dynamical KMS symmetry, to which we refer as the special dynamical KMS condition. In particular, we prove a theorem stating that a system satisfying the special dynamical KMS condition is always supersymmetrizable. We discuss a number of examples explicitly, including model A for dynamical critical phenomena, a hydrodynamic theory of nonlinear diffusion, and fluctuating hydrodynamics for relativistic charged fluids.

   ↳ hep-thcond-mat.stat-mechhep-phmath-ph+1JHEP(2018)·29 citations
8. 08*

   Möbius domain-wall fermions on gradient-flowed dynamical HISQ ensembles

   Evan Berkowitz🇩🇪 · Chris Bouchard🇺🇸 · Chia Cheng Chang🇺🇸 · M. A. Clark🇺🇸 · Balint Joo🇺🇸 · Thorsten Kurth🇺🇸 · Christopher Monahan🇺🇸 · Amy Nicholson🇺🇸 · Kostas Orginos🇺🇸 · Enrico Rinaldi🇺🇸 · Pavlos Vranas🇺🇸 · Andre Walker-Loud🇺🇸

   We report on salient features of a mixed lattice QCD action using valence Möbius domain-wall fermions solved on the dynamical $N_f=2+1+1$ HISQ ensembles generated by the MILC Collaboration. The approximate chiral symmetry properties of the valence fermions are shown to be significantly improved by utilizing the gradient-flow scheme to first smear the HISQ configurations. The greater numerical cost of the Möbius domain-wall inversions is mitigated by the highly efficient QUDA library optimized for NVIDIA GPU accelerated compute nodes. We have created an interface to this optimized QUDA solver in Chroma. We provide tuned parameters of the action and performance of QUDA using ensembles with the lattice spacings $a\simeq \{0.15,0.12,0.09\}$ fm and pion masses $m_{\pi }\simeq \{310,220,130\}$ MeV. We have additionally generated two new ensembles with $a\sim 0.12$ fm and $m_{\pi }\sim \{400,350\}$ MeV. With a fixed flow-time of $t_{gf}=1$ in lattice units, the residual chiral symmetry breaking of the valence fermions is kept below 10\% of the light quark mass on all ensembles, $m_{res}\lesssim 0.1\times m_l$, with moderate values of the fifth dimension $L_5$ and a domain-wall height $M_5\le 1.3$. As a benchmark calculation, we perform a continuum, infinite volume, physical pion and kaon mass extrapolation of $F_{K^{\pm }}/F_{{\pi }^{\pm }}$ and demonstrate our results are independent of flow-time, and consistent with the FLAG determination of this quantity at the level of less than one standard deviation.

   ↳ hep-lathep-phnucl-thPRD(2017)·33 citations
9. 09*

   Few-body approach to structure of $\bar{K}$-nuclear quasi-bound states

   Shota Ohnishi🇯🇵 · Wataru Horiuchi🇯🇵 · Tsubasa Hoshino🇯🇵 · Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵

   Structure of light antikaon-nuclear quasi-bound states, which consist of an antikaon $(\bar{K}=K^{-},{\bar{K}}^0)$ and a few nucleons $(N=p,n)$ such as $\bar{K}NN$, $\bar{K}NNN$, $\bar{K}NNNN$ and $\bar{K}NNNNNN$ systems, is studied with full three- to seven-body calculations. Employing a realistic $\bar{K}N$ potential based on the chiral SU(3) effective field theory with the SIDDHARTA constraint, we show that the central nucleon densities of these systems increases when the antikaon is injected, by about factor of two at maximum. The $\bar{K}NNNN$ system shows the largest central density, about 0.74 fm${}^{-3}$ even with the phenomenological $\bar{K}N$ potential, which are not as high as those suggested in previous studies with approximate treatments of the few-body systems. We find the spin of the ground state of the $\bar{K}NNNNNN$ system depends on the strength of the $\bar{K}N$ attraction. Thus, the quantum number of the ground state can be another constraint on the $\bar{K}N$ interaction.

   ↳ nucl-thhep-phPRC(2017)·43 citations
10. 10*

    On the possible enhancement of the dark matter density distribution at the galactic center

    V. Gammaldi🇮🇹 · V. Avila-Reese🇲🇽 · O. Valenzuela🇲🇽 · A. X. Gonzalez-Morales🇲🇽 · P. Salucci🇮🇹 · F. Nesti🇭🇷

    The dark matter spike induced by the adiabatic growth of a massive black hole in a cuspy environment, may explain the thermal dark matter density required to fit the cut-off in the HESSJ1745-290 gamma-ray spectra as TeV dark matter signal with a background component. The spike extension appears comparable with the HESS angular resolution.

    ↳ astro-ph.GAastro-ph.COastro-ph.HEhep-phRev.Mex.Astron.Astrof.Ser.Conf.(2017)·1 citation
11. 11*

    Beyond the Standard Model: Charting Fundamental Interactions via Lattice Simulations

    Claudio Pica🇩🇰

    After the discovery of the Higgs boson, the primary objective of the Large Hadron Collider (LHC) experiments is to identify new physics beyond the Standard Model (SM). One of the most intriguing possibilities would be the discovery of non-perturbative phenomena in electroweak physics. In fact both ATLAS and CMS are providing crucial precision tests of the Higgs sector. Most strikingly, there is no conclusive evidence yet on whether the Higgs boson is elementary or composite. Lattice simulations can play a key role in advancing our theoretical understanding of strongly coupled gauge theories relevant for extensions of the SM and the LHC program. In this talk I will review the state of beyond the SM (BSM) lattice studies aimed to chart the phase diagram and to uncover the properties of strongly coupled gauge theories.

    ↳ hep-lathep-phPoS(2016)·39 citations
12. 12*

    Effective field theory for dissipative fluids (II): classical limit, dynamical KMS symmetry and entropy current

    Paolo Glorioso🇺🇸 · Michael Crossley🇺🇸 · Hong Liu🇺🇸

    In this paper we further develop the fluctuating hydrodynamics proposed in arXiv:1511.03646 in a number of ways. We first work out in detail the classical limit of the hydrodynamical action, which exhibits many simplifications. In particular, this enables a transparent formulation of the action in physical spacetime in the presence of arbitrary external fields. It also helps to clarify issues related to field redefinitions and frame choices. We then propose that the action is invariant under a $Z_2$ symmetry to which we refer as the dynamical KMS symmetry. The dynamical KMS symmetry is physically equivalent to the previously proposed local KMS condition in the classical limit, but is more convenient to implement and more general. It is applicable to any states in local equilibrium rather than just thermal density matrix perturbed by external background fields. Finally we elaborate the formulation for a conformal fluid, which contains some new features, and work out the explicit form of the entropy current to second order in derivatives for a neutral conformal fluid.

    ↳ hep-thcond-mat.stat-mechgr-qchep-ph+2JHEP(2017)·160 citations
13. 13*

    The large-N Yang-Mills S-matrix is ultraviolet finite, but the large-N QCD S-matrix is only renormalizable

    Marco Bochicchio🇮🇹

    YM and QCD are known to be renormalizable, but not ultraviolet finite, order by order in perturbation theory. It is a fundamental question as to whether YM or QCD are ultraviolet finite, or only renormalizable, order by order in the large-N 't Hooft or Veneziano expansions. We demonstrate that Renormalization Group and Asymptotic Freedom imply that in 't Hooft large-N expansion the S-matrix in YM is ultraviolet finite, while in both 't Hooft and Veneziano large-N expansions the S-matrix in confining QCD with massless quarks is renormalizable but not ultraviolet finite. By the same argument it follows that the large-N $\mathcal{N}=1$ SUSY YM S-matrix is ultraviolet finite as well. Besides, we demonstrate that the correlators of local gauge-invariant operators, as opposed to the S-matrix, are renormalizable but in general not ultraviolet finite in the large-N 't Hooft and Veneziano expansions, neither in pure YM and $\mathcal{N}=1$ SUSY YM nor a fortiori in massless QCD. Moreover, we compute explicitly the counterterms that arise renormalizing the large-N 't Hooft and Veneziano expansions, by deriving in confining massless QCD-like theories a low-energy theorem of NSVZ type, that relates the log derivative with respect to the gauge coupling of a $k$-point correlator, or the log derivative with respect to the RG-invariant scale, to a $k+1$-point correlator with the insertion of $Tr{F}^2$ at zero momentum. Finally, we argue that similar results hold in the large-N limit of a vast class of confining QCD-like theories with massive matter fields, provided a renormalization scheme exists, as for example $\overline{MS}$, in which the beta function is independent on the masses. In particular, in both 't Hooft and Veneziano large-N expansions the S-matrix in confining massive QCD and massive $\mathcal{N}=1$ SUSY QCD is renormalizable but not ultraviolet finite.

    ↳ hep-thhep-phPRD(2017)·14 citations
14. 14*

    New Energy-Momentum and Angular Momentum Tensors with Applications to Nucleon Structure

    Zhen-Lai Wang🇨🇳 · De-Tian Yang🇨🇳 · Zi-Wei Chen🇨🇳 · Tao Lei🇨🇳 · Xiang-Song Chen🇨🇳

    We present a new type of energy-momentum tensor and angular momentum tensor. They are motivated by a special consideration in quantum measurement: Given a wave in mutual eigen-state of more than one physical observables, the corresponding physical currents should be proportional to each other. Interestingly, this criterion denies the traditional canonical and symmetric expressions of energy-momentum tensor and their associated expressions of angular momentum tensor. The new tensors we propose can be derived as Noether currents from a Lagrangian with second derivative, and shed new light on the study of nucleon structures.

    ↳ physics.gen-phhep-ph1 citation

* 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.