HEP Phenomenology·hep-ph

Mon·Aug 3, 2015Monday·August 3, 2015

29 papers—19 primary·10 cross-listed·reconstructed*

01*
Heavy $Q ˉ Q$ free energy from hadronic states
E. Megias🇩🇪 · E. Ruiz Arriola🇪🇸 · L.L. Salcedo🇪🇸
Within the spirit of the Hadron Resonance Gas model, we study a representation of the heavy $Q ˉ Q$ free energy at temperatures below the phase transition in terms of the string and heavy-light hadrons. We discuss the string breaking phenomenon and the relevance of avoided crossings between the fundamental string and the hadron spectrum. Good agreement with lattice data is achieved.
hep-phhep-lathep-thnucl-thNucl.Part.Phys.Proc.(2016)·3 citations
02*
The $ν$ generation: present and future constraints on neutrino masses from cosmology and laboratory experiments
Martina Gerbino🇮🇹 · Massimiliano Lattanzi🇮🇹 · Alessandro Melchiorri🇮🇹
We perform a joint analysis of current data from cosmology and laboratory experiments to constrain the neutrino mass parameters in the framework of bayesian statistics, also accounting for uncertainties in nuclear modeling, relevant for neutrinoless double $β$ decay ( $0 ν 2 β$ ) searches. We find that a combination of current oscillation, cosmological and $0 ν 2 β$ data constrains $m_{β β} < 0.045 eV$ ( $0.014 eV < m_{β β} < 0.066 eV$ ) at 95\% C.L. for normal (inverted) hierarchy. This result is in practice dominated by the cosmological and oscillation data, so it is not affected by uncertainties related to the interpretation of $0 ν 2 β$ data, like nuclear modeling, or the exact particle physics mechanism underlying the process. We then perform forecasts for forthcoming and next-generation experiments, and find that in the case of normal hierarchy, given a total mass of $0.1$ eV, and assuming a factor-of-two uncertainty in the modeling of the relevant nuclear matrix elements, it will be possible to measure the total mass itself, the effective Majorana mass and the effective electron mass with an accuracy (at 95\% C.L.) of $0.05$ , $0.015$ , $0.02 eV$ respectively, as well as to be sensitive to one of the Majorana phases. This assumes that neutrinos are Majorana particles and that the mass mechanism gives the dominant contribution to $0 ν 2 β$ decay. We argue that more precise nuclear modeling will be crucial to improve these sensitivities.
hep-phastro-ph.COPRD(2016)·29 citations
03*
On the low-x NLO evolution of 4 point colorless operators
A. V. Grabovsky🇷🇺
The NLO evolution equations for quadrupole and double dipole operators have been obtained within the high energy operator expansion method. The corresponding quasi-conformal evolution equations for the composite operators were constructed.
hep-phJHEP(2015)·3 citations
04*
On the importance of direct detection combined limits for spin independent and spin dependent dark matter interactions
Cristina Marcos🇪🇸 · Miguel Peiro🇪🇸 · Sandra Robles🇪🇸
In this work we show how the inclusion of dark matter (DM) direct detection upper bounds in a theoretically consistent manner can affect the allowed parameter space of a DM model. Traditionally, the limits from DM direct detection experiments on the elastic scattering cross section of DM particles as a function of their mass are extracted under simplifying assumptions. Relaxing the assumptions related to the DM particle nature, such as the neutron to proton ratio of the interactions, or the possibility of having similar contributions from the spin independent (SI) and spin dependent (SD) interactions can vary significantly the upper limits. Furthermore, it is known that astrophysical and nuclear uncertainties can also affect the upper bounds. To exemplify the impact of properly including all these factors, we have analysed two well motivated and popular DM scenarios: neutralinos in the NMSSM and a Z' portal with Dirac DM. We have found that the allowed parameter space of these models is subject to important variations when one includes both the SI and SD interactions at the same time, realistic neutron to proton ratios, as well as using different self-consistent speed distributions corresponding to popular DM halo density profiles, and distinct SD structure functions. Finally, we provide all the necessary information to include the upper bounds of SuperCDMS and LUX taking into account all these subtleties in the investigation of any particle physics model. The data for each experiment and example codes are available at this site http://goo.gl/1CDFYi, and their use is detailed in the appendices of this work.
hep-phJCAP(2016)·14 citations
05*
Relaxing the Electroweak Scale: the Role of Broken dS Symmetry
Subodh P. Patil🇨🇭 · Pedro Schwaller🇨🇭
Recently, a novel mechanism to address the hierarchy problem has been proposed \cite{Graham:2015cka}, where the hierarchy between weak scale physics and any putative `cutoff' $M$ is translated into a parametrically large field excursion for the so-called relaxion field, driving the Higgs mass to values much less than $M$ through cosmological dynamics. In its simplest incarnation, the relaxion mechanism requires nothing beyond the standard model other than an axion (the relaxion field) and an inflaton. In this note, we critically re-examine the requirements for successfully realizing the relaxion mechanism and point out that parametrically larger field excursions can be obtained for a given number of e-folds by simply requiring that the background break exact de Sitter invariance. We discuss several corollaries of this observation, including the interplay between the upper bound on the scale $M$ and the order parameter $ϵ$ associated with the breaking of dS symmetry, and entertain the possibility that the relaxion could play the role of a curvaton. We find that a successful realization of the mechanism is possible with as few as $O (1 0^{3})$ e-foldings, albeit with a reduced cutoff $M \sim 1 0^{6}$ GeV for a dark QCD axion and outline a minimal scenario that can be made consistent with CMB observations.
hep-phastro-ph.COhep-thJHEP(2016)·54 citations
06*
Inflatable Dark Matter
Hooman Davoudiasl🇺🇸 · Dan Hooper🇺🇸 · Samuel D. McDermott🇺🇸
We describe a general scenario, dubbed "Inflatable Dark Matter", in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early universe. The overproduction of dark matter that is predicted within many otherwise well-motivated models of new physics can be elegantly remedied within this context, without the need to tune underlying parameters or to appeal to anthropic considerations. Thermal relics that would otherwise be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the non-thermal abundance of GUT or Planck scale axions can be brought to acceptable levels, without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ~ MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the Standard Model.
hep-phastro-ph.COhep-thPRL(2016)·78 citations
07*
$K \to π ν ν ˉ$ and $ϵ^{'} / ϵ$ in Simplified New Physics Models
Andrzej J. Buras🇩🇪 · Dario Buttazzo🇩🇪 · Robert Knegjens🇩🇪
The decays $K^{+} \to π^{+} ν ν ˉ$ and $K_{L} \to π^{0} ν ν ˉ$ , being the theoretically cleanest rare decays of mesons, are very sensitive probes of New Physics. In view of the excellent prospects of reaching the Standard Model sensitivity for $K^{+} \to π^{+} ν ν ˉ$ by the NA62 experiment at CERN and for $K_{L} \to π^{0} ν ν ˉ$ by the KOTO experiment at J-PARC, we study them in the simplest extensions of the SM in which stringent correlations between these two decays and other flavour observables are present. We first consider simple models with tree-level Z and Z' contributions in which either MFV or a $U (2)^{3}$ symmetry is imposed on the quark flavour-violating couplings. We then compare the resulting correlations with those present in generic models in which the latter couplings are arbitrary, subject to constraints from $Δ F = 2$ processes, electroweak and collider data. Of particular interest are the correlations with $ϵ^{'} / ϵ$ and $K_{L} \to μ^{+} μ^{-}$ which limit the size of NP contributions to $K^{+} \to π^{+} ν ν ˉ$ and $K_{L} \to π^{0} ν ν ˉ$ , depending on the Dirac structure of couplings and the relevant operators. But in MFV also the constraint from $B_{s} \to μ^{+} μ^{-}$ turns out to be important. We take into account the recent results from lattice QCD and large N approach that indicate $ϵ^{'} / ϵ$ in the SM to be significantly below the data. While in many models the enhancement of $ϵ^{'} / ϵ$ implies a suppression of $K_{L} \to π^{0} ν ν ˉ$ , we present two models in which these observables can be simultaneously enhanced relative to SM predictions. A correlation between $K^{+} \to π^{+} ν ν ˉ$ and $B \to K (K^{*}) μ^{+} μ^{-}$ , found by us in the simple models considered here, should be of interest for NA62 and LHCb experimentalists at CERN in the coming years. The one with $B \to K (K^{*}) ν ν ˉ$ will be tested at Belle II.
hep-phhep-exhep-latJHEP(2015)·194 citations
08*
Higgsophilic gauge bosons and monojets at the LHC
Jong Soo Kim🇪🇸 · Oleg Lebedev🇫🇮 · Daniel Schmeier🇩🇪
We consider a generic framework where the Standard Model (SM) coexists with a hidden sector endowed with some additional gauge symmetry. When this symmetry is broken by a scalar field charged under the hidden gauge group, the corresponding scalar boson generally mixes with the SM Higgs boson. In addition, massive hidden gauge bosons emerge and via the mixing, the observed Higgs-like mass eigenstate is the only known particle that couples to these hidden gauge bosons directly. We study the LHC monojet signatures of this scenario and the corresponding constraints on the gauge coupling of the hidden gauge group as well as the mixing of the Higgs scalars.
hep-phJHEP(2015)·19 citations
09*
Study on accelerator neutrino detection at a spallation source
Ming-Yang Huang🇨🇳
In this paper, we study the detection of accelerator neutrinos produced at the China Spallation Neutron Source (CSNS). Using the code FLUKA, we have simulated the production of neutrinos in the proton beam on the tungsten target and obtained the yield efficiency, numerical flux, and average energy of different flavors of neutrinos. Furthermore, detections of these accelerator neutrinos are investigated in two reaction channels, the neutrino-electron reactions and neutrino-carbon reactions. The event numbers of different flavors of neutrinos have also been calculated.
hep-phphysics.ins-detCPC(2016)·6 citations
10*
Polyakov--Nambu--Jona-Lasinio model in finite volumes
Abhijit Bhattacharyya🇮🇳 · Sanjay K. Ghosh🇮🇳 · Rajarshi Ray🇮🇳 · Kinkar Saha🇮🇳 · Sudipa Upadhaya🇮🇳
We discuss the 2+1 flavor Polyakov loop enhanced Nambu--Jona-Lasinio model in a finite volume. The main objective is to check the volume scaling of thermodynamic observables for various temperatures and chemical potentials. We observe the possible violation of the scaling with system size in a considerable window along the whole transition region in the $T - μ_{q}$ plane.
hep-phnucl-thEPL(2016)·27 citations
11*
A Complete Two-Loop, Five-Gluon Helicity Amplitude in Yang-Mills Theory
Simon Badger🇬🇧 · Gustav Mogull🇬🇧 · Alexander Ochirov🇬🇧 · Donal O'Connell🇬🇧
We compute the integrand of the full-colour, two-loop, five-gluon scattering amplitude in pure Yang-Mills theory with all helicities positive, using generalized unitarity cuts. Tree-level BCJ relations, satisfied by amplitudes appearing in the cuts, allow us to deduce all the necessary non-planar information for the full-colour amplitude from known planar data. We present our result in terms of irreducible numerators, with colour factors derived from the multi-peripheral colour decomposition. Finally, the leading soft divergences are checked to reproduce the expected infrared behaviour.
hep-phhep-thJHEP(2015)·120 citations
12*
Stability and UV completion of the Standard Model
Vincenzo Branchina🇮🇹 · Emanuele Messina🇮🇹
The knowledge of the stability condition of the electroweak (EW) vacuum is of the greatest importance for our understanding of beyond Standard Model (BSM) physics. It is widely believed that new physics that lives at very high energy scales should have no impact on the stability analysis. This expectation has been recently challenged, but the results were controversial as new physics was given in terms of non-renormalizable higher order operators. Here we consider for the first time a renormalizable (toy) UV completion of the SM, and definitely show that such a decoupling does not take place. This result has important phenomenological consequences, providing a very useful test for BSM theories. In particular, it shows that speculations based on the so called "criticality" do not appear to be well founded.
hep-phEPL(2017)·51 citations
13*
The Higgs boson structure functions as signposts of new physics
G.J. Gounaris🇬🇷 · F.M. Renard🇫🇷
We show that the Higgs boson structure functions observable in the inclusive process $e^{-} e^{+} \to H + "anything"$ may reveal the presence of anomalous contributions corresponding to several types of new physics partners, Higgs boson compositeness or invisible (dark) matter. This could be done without making a difficult or even an impossible experimental analysis of the contents of the "anything". We give illustrations showing how the shapes of the various structure functions containing such typical new contributions may differ from the standard prediction and allow their identification.
hep-phPRD(2015)·3 citations
14*
Stability of the Electroweak Vacuum: Gauge Independence and Advanced Precision
A.V. Bednyakov🇷🇺 · B.A. Kniehl🇩🇪 · A.F. Pikelner🇩🇪 · O.L. Veretin🇩🇪
We perform a manifestly gauge-independent analysis of the vacuum stability in the Standard Model (SM) including two-loop matching, three-loop renormalization group evolution, and pure QCD corrections through four loops. All these ingredients are exact, except that light-fermion masses are neglected. We in turn apply the criterion of nullifying the $MS$ Higgs self-coupling and its beta function and a recently proposed consistent method for determining the true minimum of the effective Higgs potential that also avoids gauge dependence. Exploiting our knowledge of the Higgs-boson mass, we derive an upper bound on the pole mass of the top quark by requiring that the SM be stable all the way up to the Planck mass scale and conservatively estimate the theoretical uncertainty. This bound is compatible with Monte Carlo mass quoted by the Particle Data Group at the $1.3 σ$ level.
hep-phgr-qchep-exhep-thPRL(2015)·324 citations
15*
Neutral Triple Vector Boson Production in Randall-Sundrum Model at the LHC
Goutam Das🇮🇳 · Prakash Mathews🇮🇳
In this paper, triple neutral electroweak gauge boson production processes, viz. \gamma\gamma\gamma, \gamma\gamma Z, \gamma ZZ and ZZZ productions merged to 1-jet have been studied at the leading order in QCD in the context of Randall-Sundrum model at the LHC with center of mass energy \sqrt{S}=13 TeV. Decay of Z bosons into lepton-pairs has been considered. We present a selection of kinematical distributions matched to parton shower and show their deviation from the SM results as a result of the RS model. The uncertainties as a result of the factorization and renormalization scales are also presented.
hep-phhep-exPRD(2015)·10 citations
16*
Axionic suppression of plasma wakefield acceleration
D.A. Burton🇬🇧 · A. Noble🇬🇧 · T.J. Walton🇬🇧
Contemporary attempts to explain the existence of ultra-high energy cosmic rays using plasma-based wakefield acceleration deliberately avoid non-Standard Model particle physics. However, such proposals exploit some of the most extreme environments in the Universe and it is conceivable that hypothetical particles outside the Standard Model have significant implications for the effectiveness of the acceleration process. Axions solve the strong CP problem and provide one of the most important candidates for Cold Dark Matter, and their potential significance in the present context should not be overlooked. Our analysis of the field equations describing a plasma augmented with axions uncovers a dramatic axion-induced suppression of the energy gained by a test particle in the wakefield driven by a particle bunch, or an intense pulse of electromagnetic radiation, propagating at ultra-relativistic speeds within the strongest magnetic fields in the Universe.
hep-phphysics.acc-phphysics.plasm-phJ.Phys.A(2016)·6 citations
17*
Caustic structures in the spectrum of x-ray Compton scattering off electrons driven by a short intense laser pulse
D. Seipt🇩🇪 · A. Surzhykov🇩🇪 · S. Fritzsche🇩🇪 · B. Kampfer🇩🇪
We study the Compton scattering of x-rays off electrons that are driven by a relativistically intense short optical laser pulse. The frequency spectrum of the laser-assisted Compton radiation shows a broad plateau in the vicinity of the laser-free Compton line due to a nonlinear mixing between x-ray and laser photons. Special emphasis is placed on how the shape of the short assisting laser pulse affects the spectrum of the scattered x-rays. In particular, we observe sharp peak structures in the plateau region, whose number and locations are highly sensitive to the laser pulse shape. These structures are interpreted as spectral caustics by using a semiclassical analysis of the laser-assisted QED matrix element.
hep-phphysics.atom-phphysics.plasm-phNew J.Phys.(2016)·25 citations
18*
On the intrinsic bottom content of the nucleon
Florian Lyonnet🇺🇸 · Aleksander Kusina🇫🇷 · Karol Kovařík🇩🇪 · Tomáš Ježo🇮🇹 · Fred Olness🇺🇸 · Ingo Schienbein🇫🇷 · Ji-Young Yu🇺🇸
We demonstrate that to a very good approximation the scale-evolution of the intrinsic heavy quark content of the nucleon is governed by non-singlet evolution equations. This allows us to analyze the intrinsic heavy quark distributions without having to resort to a full-fledged global analysis of parton distribution functions. This freedom is then exploited to model intrinsic bottom distributions which are so far missing in the literature in order to estimate the impact of this non-perturbative contribution to the bottom-quark PDF, and on parton--parton luminosities at the LHC. This technique can be applied to the case of intrinsic charm, albeit within the limitations outlined in the following.
hep-phPoS(2015)·2 citations
19*
The impact of quark masses on pQCD thermodynamics
Thorben Graf🇩🇪 · Juergen Schaffner-Bielich🇩🇪 · Eduardo S. Fraga🇧🇷
We present results for several thermodynamic quantities within the next-to-leading order calculation of the thermodynamic potential in perturbative QCD at finite temperature and chemical potential including non-vanishing quark masses. These results are compared to lattice data and to higher-order optimized perturbative calculations to investigate the trend brought about by mass corrections.
hep-phnucl-thEPJA(2016)·22 citations
20*
Component action of nilpotent multiplet coupled to matter in 4 dimensional $N = 1$ supergravity
Fuminori Hasegawa🇯🇵 · Yusuke Yamada🇯🇵
We construct the component action of the system including an ordinary matter and a nilpotent multiplet in global and local supersymmetric framework. The higher dimensional operators of not only Goldstino but also matter and gravitino fields are shown, which appear due to nonlinearly realized supersymmetry.
↳ hep-thhep-phJHEP(2015)·106 citations
21*
Towards discrimination between galactic and intergalactic axion-photon mixing
Sergey Troitsky🇷🇺
There exists a growing evidence for the anomalous transparency of the Universe for energetic gamma rays. Popular explanations include conversion of photons into hypothetical axion-like particles (ALPs) and back in astrophysical magnetic fields. Two distinctive scenarios of this conversion have been put forward: either it happens in the (host galaxy of the) gamma-ray source and in the Milky Way, or the photon-ALP oscillations take place in the intergalactic magnetic fields all along the way between the source and the observer. Here we point out that, given recent astrophysical constraints on ALPs and on intergalactic magnetic fields, these two mechanisms imply very different ALP masses and couplings. Therefore, confirmation of the anomalies and identification of one of the scenarios would mean cornering of ALP parameters to a particular narrow region. We discuss approaches to distinguish between the two mechanisms and present some preliminary indications in favour of the galactic scenario.
↳ astro-ph.HEhep-phPRD(2016)·21 citations
22*
AMS-02 electrons and positrons: astrophysical interpretation and Dark Matter constraints
Mattia Di Mauro🇮🇹 · Andrea Vittino🇮🇹
We present here a quantitative analysis of the recent AMS-02 data with the purpose of investigating the interplay between astrophysical sources and Dark Matter in their interpretation. First, we show that AMS-02 leptonic measurements are in a remarkably good agreement with the hypothesis that all electrons and positrons are the outcome of primary or secondary astrophysical processes. Then, we add Dark Matter to the picture, in order to establish which are the informations on its annihilation cross section (or lifetime) that can be inferred by fitting AMS-02 data within a scenario in which Dark Matter and astrophysical sources jointly contribute to the different leptonic observables. In particular, by performing a Markov Chain Monte Carlo sampling of the parameters space of the theory, we attempt at characterizing the significance of a possible Dark Matter contribution to the observed data and we derive robust upper limits on the Dark Matter annihilation/decay rate.
↳ astro-ph.HEhep-phPoS(2016)·8 citations
23*
Impact Factors for Reggeon-Gluon Transitions
V.S. Fadin🇷🇺
General expressions for the impact factors up to terms vanishing at the space-time dimension $D \to 4$ are presented. Their infrared behaviour is analysed and calculation of exact in $D \to 4$ asymptotics at small momenta of Reggeized gluons is discussed.
↳ hep-thhep-ph6 citations
24*
Shear and Bulk Viscosities of Quark Matter from Quark-Meson Fluctuations in the Nambu--Jona-Lasinio model
Sabyasachi Ghosh🇧🇷 · Thiago C. Peixoto🇧🇷 · Victor Roy🇩🇪 · Fernando E. Serna🇧🇷 · Gastão Krein🇧🇷
We have calculated the temperature dependence of shear $η$ and bulk $ζ$ viscosities of quark matter due to quark-meson fluctuations. The quark thermal width originating from quantum fluctuations of quark- $π$ and quark- $σ$ loops at finite temperature is calculated with the formalism of real-time thermal field theory. Temperature-dependent constituent-quark and meson masses, and quark-meson couplings are obtained in the Nambu--Jona-Lasinio model. We found a non-trivial influence of the temperature-dependent masses and couplings on the Landau-cut structure of the quark self-energy. Our results for the ratios $η / s$ and $ζ / s$ , where $s$ is the entropy density (also determined in the Nambu--Jona-Lasinio model in the quasi-particle approximation), are in fair agreement with results of the literature obtained from different models and techniques. In particular, our result for $η / s$ has a minimum very close to the conjectured AdS/CFT lower bound, $η / s = 1/4 π$ .
↳ nucl-thhep-phPRC(2016)·57 citations
25*
Longitudinal vector form factors in weak decays of nuclei
F. Simkovic🇸🇰 · S. Kovalenko🇨🇱 · M. I. Krivoruchenko🇷🇺
The longitudinal form factors of the weak vector current of particles with spin $J = 1/2$ and isospin $I = 1/2$ are determined by the mass difference and the charge radii of members of the isotopic doublets. The most promising reactions to measure these form factors are the reactions with large momentum transfers involving the spin-1/2 isotopic doublets with a maximum mass splitting. Numerical estimates of longitudinal form factors are given for nucleons and eight nuclear spin-1/2 isotopic doublets.
↳ nucl-thhep-phAIP Conf.Proc.(2015)·0 citations
26*
nuSTORM: Neutrinos from Stored Muons
F.J.P. Soler🇬🇧
nuSTORM (Neutrinos from STORed Muons) is a proposed storage ring facility to deliver beams of muon antineutrinos and electron neutrinos from positive muon decays (muon neutrinos and electron antineutrinos from negative muon decays), with a central muon momentum of 3.8 GeV/c and a momentum acceptance of 10%. The facility will allow searches for eV-scale sterile neutrinos at better than 10 sigma sensitivity, it will be able to provide measurements of neutrino and antineutrino-nucleus scattering cross sections with percent-level precision and will serve as a first step towards developing muon accelerators for particle physics. We report on the physics capabilities of the nuSTORM facility and we specify the main features of its design, which does not require any new technology. The flux of the neutrino beam can be determined with percent-level accuracy to perform cross-section measurements for future neutrino oscillation experiments and to resolve the hints for eV-scale sterile neutrinos. nuSTORM may be considered as a first step towards a Neutrino Factory and a Muon Collider.
↳ physics.ins-dethep-exhep-ph7 citations
27*
Generalized Parametrization Dependence in Quantum Gravity
Holger Gies🇩🇪 · Benjamin Knorr🇩🇪 · Stefan Lippoldt🇩🇪
We critically examine the gauge, and field-parametrization dependence of renormalization group flows in the vicinity of non-Gauß{}ian fixed points in quantum gravity. While physical observables are independent of such calculational specifications, the construction of quantum gravity field theories typically relies on off-shell quantities such as $β$ functions and generating functionals and thus face potential stability issues with regard to such generalized parametrizations. We analyze a two-parameter class of covariant gauge conditions, the role of momentum-dependent field rescalings and a class of field parametrizations. Using the product of Newton and cosmological constant as an indicator, the principle of minimum sensitivity identifies stationary points in this parametrization space which show a remarkable insensitivity to the parametrization. In the most insensitive cases, the quantized gravity system exhibits a non-Gauß{}ian UV stable fixed point, lending further support to asymptotically free quantum gravity. One of the stationary points facilitates an analytical determination of the quantum gravity phase diagram and features ultraviolet and infrared complete RG trajectories with a classical regime.
↳ hep-thgr-qchep-phPRD(2015)·149 citations
28*
Massive photons: an infrared regularization scheme for lattice QCD+QED
Michael G. Endres🇺🇸 · Andrea Shindler🇩🇪 · Brian C. Tiburzi🇺🇸 · Andre Walker-Loud🇺🇸
Standard methods for including electromagnetic interactions in lattice quantum chromodynamics calculations result in power-law finite-volume corrections to physical quantities. Removing these by extrapolation requires costly computations at multiple volumes. We introduce a photon mass to alternatively regulate the infrared, and rely on effective field theory to remove its unphysical effects. Electromagnetic modifications to the hadron spectrum are reliably estimated with a precision and cost comparable to conventional approaches that utilize multiple larger volumes. A significant overall cost advantage emerges when accounting for ensemble generation. The proposed method may benefit lattice calculations involving multiple charged hadrons, as well as quantum many-body computations with long-range Coulomb interactions.
↳ hep-lathep-phnucl-thPRL(2016)·91 citations
29*
Thermodynamics of QCD from Sakai-Sugimoto Model
Hiroshi Isono🇹🇼 · Gautam Mandal🇮🇳 · Takeshi Morita🇯🇵
Till date, the only consistent description of the deconfinement phase of the Sakai-Sugimoto model appears to be provided by the analysis of [1] (arXiv:1107.4048). The current version of the analysis, however, has a subtlety regarding the monodromy of quarks around the Euclidean time circle. In this note, we revisit and resolve this issue by considering the effect of an imaginary baryon chemical potential on quark monodromies. With this ingredient, the proposal of [1] for investigating finite temperature QCD using holography is firmly established. Additionally, our technique allows a holographic computation of the free energy as a function of the imaginary chemical potential in the deconfinement phase; we show that our result agrees with the corresponding formula obtained from perturbative QCD, namely the Roberge-Weiss potential.
↳ hep-thhep-phJHEP(2015)·9 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.