HEP Phenomenology·hep-ph

Tue·Aug 29, 2017Tuesday·August 29, 2017

29 papers—23 primary·6 cross-listed·reconstructed*

01*
Hidden Spin-3/2 Field in the Standard Model
Durmuş Demir🇹🇷 · Canan Karahan🇹🇷 · Beste Korutlu🇹🇷 · Ozan Sargın🇹🇷
Here we show that a massive spin-3/2 field can hide in the SM spectrum in a way revealing itself only virtually. We study collider signatures and loop effects of this field, and determine its role in Higgs inflation and its potential as Dark Matter. We show that this spin-3/2 field has a rich linear collider phenomenology and motivates consideration of a neutrino-Higgs collider. We also show that study of Higgs inflation, dark matter and dark energy can reveal more about the neutrino and dark sector.
hep-phEPJC(2017)·5 citations
02*
TMD splitting functions and the corresponding evolution equation
A. Kusina🇫🇷
We generalize the Catani Hautmann formalism to calculate the Pgq and Pqq transverse momentum dependent splitting functions. Then we use the obtained Pgq kernel to construct a low-x evolution equation for gluons that takes into account the effect of non-diagonal quark-to-gluon splittings. In order to write down a consistent equation we resum virtual corrections coming from the gluon channel and demonstrate that this implies a suitable regularization of the Pgq singularity, corresponding to a soft emitted quark. We also note that the obtained equation is in a straightforward manner generalized to a nonlinear evolution equation which takes into account effects due to the presence of high gluon densities.
hep-phPoS(2018)·0 citations
03*
Probe CP violation in $H \to γ Z$ through forward-backward asymmetry
Xia Wan🇨🇳
We suggest that the forward-backward asymmetry $(A_{F B})$ of the charged lepton in $g g \to H \to γ Z \to γ ℓ^{-} ℓ^{+}$ process could be used to probe the CP violating $H γ Z$ coupling when the interference from $g g \to γ Z \to γ ℓ^{-} ℓ^{+}$ process is included. With CP violation in $H γ Z$ coupling, the interference effect leads to a non-vanishing $A_{F B}$ , which is also sensitive to the strong phase differences. The resonant and non-resonant strong phases together make $A_{F B} (s^)$ change sign around Higgs mass $M_{H}$ . For phenomenology study, we suggest the integral over one-side mass region below $M_{H}$ to magnify the $A_{F B}$ strength.
hep-ph0 citations
04*
$C P$ violation in charmed hadron decays into neutral kaons
Di Wang🇨🇳 · Fu-Sheng Yu🇨🇳 · Hsiang-nan Li🇹🇼
We find a new $C P$ violating effect in charmed hadron decays into neutral kaons, which is induced by the interference between the Cabibbo-favored and doubly Cabibbo-suppressed amplitudes with the $K^{0} - K^{0}$ mixing. It is estimated to be of order of $O (1 0^{- 3})$ , much larger than the direct $C P$ asymmetry, but missed in the literature. To reveal this new $C P$ violation effect, we propose a new observable, the difference of the $C P$ asymmetries in the $D^{+} \to π^{+} K_{S}^{0}$ and $D_{s}^{+} \to K^{+} K_{S}^{0}$ modes. Once the new effect is determined by experiments, the direct $C P$ asymmetry then can be extracted and used to search for new physics.
hep-phPoS(2017)·0 citations
05*
Effect of two loop correction in the formation of QGP droplet
S. Somorendro Singh🇮🇳
The effect of two loop correction in the formation of quark-gluon plasma (QGP) droplet is studied with the introduction of the two loop correction factor in the mean field potential. Due to the correction factor it shows stability in the droplet formation of QGP indicating at different parametrization factors of the QGP fluid. The correction factor in the potential also shows gluon parameter factor shifts to a larger value from its earlier value of gluon factor of one loop correction in obtaining the stable droplets. The results show decreasing in the observable QGP droplets and droplet sizes are found to be $1.5 - 2.0$ fm radii with the two loop correction. It indicates that there is parameter like Reynold's number which can control the dynamics of QGP droplet formation and the stability of droplet in the case of droplet formation with the two loop correction factor.
hep-phnucl-th0 citations
06*
On the Origin of Lepton and Quark Masses
Jiri Hosek · J.Adam · Jr
Gauging the flavor (family, generation, horizontal) index of the chiral fermion fields of the Standard model, for anomaly freedom extended by three sterile right-handed neutrino fields, results in asymptotically free, {\it bona fide} nonconfining $S U (3)_{f}$ quantum flavor dynamics. Approximate nonperturbative strong-coupling solutions of the corresponding Schwinger-Dyson (SD) equation for fermion self-energies give rise to the complete flavor symmetry breaking by : (1) Three huge Majorana masses of sterile right-handed neutrinos. (2) Three exponentially light Dirac masses common to all fermion sorts in a family. Masses of charged leptons and quarks are further distinguished from Dirac neutrino masses by the weak hypercharge contributions to the universal $S U (3)_{f}$ kernel of the SD equation, free of unknown parameters. The $S U (3)_{f}$ dynamics itself thus gives the neutrino mass spectrum in the seesaw form.
hep-ph1 citation
07*
Collectivity from interference
Boris Blok🇮🇱 · Christian D. Jäkel🇧🇷 · Mark Strikman🇺🇸 · Urs Achim Wiedemann🇨🇭
In hadronic collisions, interference between different production channels affects momentum distributions of multi-particle final states. As this QCD interference does not depend on the strong coupling constant, it is part of the no-interaction baseline that needs to be controlled prior to searching for other manifestations of collective dynamics. Here, we introduce a model that is based on the QCD theory of multi-parton interactions and that allows one to study interference effects in the production of $m$ particles in hadronic collisions with $N$ parton-parton interactions ("sources"). In an expansion in powers of $1/ (N_{c}^{2} - 1)$ and to leading order in the number of sources $N$ , we calculate interference effects in the $m$ -particle spectra and we determine from them the second and fourth order cumulant momentum anisotropies $v_{n}$ . Without invoking any azimuthal asymmetry and any density dependent non-linear dynamics in the incoming state, and without invoking any interaction in the final state, we find that QCD interference alone can give rise to values for $v_{n} {2}$ and $v_{n} {4}$ , $n$ even, that persist unattenuated for increasing number of sources, that may increase with increasing multiplicity and that agree with measurements in proton-proton (pp) collisions in terms of the order of magnitude of the signal and the approximate shape of the transverse momentum dependence. We further find that the non-abelian features of QCD interference can give rise to odd harmonic anisotropies. These findings indicate that the no-interaction baseline including QCD interference effects can make a sizeable if not dominant contribution to the measured $v_{n}$ coefficients in pp collisions. Prospects for analyzing QCD interference contributions further and their possible relevance for proton-nucleus and nucleus-nucleus collisions are discussed shortly.
hep-phhep-exnucl-exnucl-thJHEP(2017)·56 citations
08*
Large degeneracy in light mesons from a modified soft-wall holographic model
S.S. Afonin🇷🇺
We propose a modification of soft-wall holographic model that in combination with the light-front holographic QCD leads to a broad hydrogen-like degeneracy of the same sort as the degeneracy observed experimentally in the spectrum of light mesons.
hep-phMod.Phys.Lett.A(2017)·6 citations
09*
Implementing nonlinear Compton scattering beyond the local constant field approximation
A. Di Piazza🇩🇪 · M. Tamburini🇩🇪 · S. Meuren🇩🇪 · C. H. Keitel🇩🇪
In the calculation of probabilities of physical processes occurring in a background classical field, the local constant field approximation (LCFA) relies on the possibility of neglecting the space-time variation of the external field within the region of formation of the process. This approximation is widely employed in strong-field QED as it allows to evaluate probabilities of processes occurring in arbitrary electromagnetic fields starting from the corresponding quantities computed in a constant electromagnetic field. Here, we demonstrate in the case of nonlinear single Compton scattering that the LCFA is quantitatively and qualitatively insufficient for describing the low-energy part of the emitted photon probability. In addition, we provide a simple recipe to implement an improved expression of the photon emission probability beyond the LCFA in numerical codes, which are an essential tool to interpret present and upcoming experiments in strong-field QED.
hep-phPRA(2018)·173 citations
10*
Direct- and Resolved-Photon Threshold Resummation for Polarized High- $p_{T}$ Hadron Production at COMPASS
Claudia Uebler🇩🇪 · Andreas Schäfer🇩🇪 · Werner Vogelsang🇩🇪
We complete our earlier study of the "direct" part of the cross section and spin asymmetry for the photoproduction process $γ N \to h X$ by analysing the "resolved" contribution, for which the photon couples like a hadron through its parton structure. The incident photon and nucleon are longitudinally polarized and one observes a hadron $h$ at high transverse momentum $p_{T}$ . Soft or collinear gluon emissions generate large logarithmic threshold corrections which we resum to next-to-leading logarithmic order. We compare our results with recent spin asymmetry data by the COMPASS collaboration, highlighting the role of the fragmentation functions.
hep-phPRD(2017)·6 citations
11*
Matter-Antimatter Asymmetry in the Universe via String-Inspired CPT Violation at Early Eras
Nick E. Mavromatos (King's College London)🇬🇧
In four-space-time dimensional string/brane theory, obtained either through compactification of the extra spatial dimensions, or by appropriate restriction to brane worlds with three large spatial dimensions, the rich physics potential associated with the presence of non-trivial Kalb-Ramond (KR) axion-like fields has not been fully exploited so far. In this talk, I discuss a scenario whereby such fields produce spontaneous Lorentz- and CPT-violating cosmological backgrounds over which strings propagate, which in the early Universe can lead to Baryogenesis through Leptogenesis in models with heavy right-handed neutrinos.
hep-phgr-qchep-thJ.Phys.Conf.Ser.(2018)·5 citations
12*
Exploring Charge and Color Breaking vacuum in Non-Holomorphic MSSM
Jyotiranjan Beuria🇮🇳 · Abhishek Dey🇮🇳
Non-Holomorphic MSSM (NHSSM) shows various promising features that are not easily obtained in MSSM. However, the additional Non-Holomorphic (NH) trilinear interactions that attribute to the interesting phenomenological features, also modify the effective scalar potential of the model significantly. We derive analytic constraints involving trilinear parameters $A_{t}^{'}$ and $A_{b}^{'}$ that exclude global charge and color breaking minima (CCB). Since the analytic constraints are obtained considering specific directions in the multi-dimensional field space, we further probe the applicability of these constraints by exhaustive scan over NH parameter space with two different regimes of $tan β$ and delineate the nature of metastability by considering vacuum expectation values for third generation squarks. We adhere to a natural scenario by fixing Higgsino mass parameter ( $μ$ ) to a low value and estimate the allowed ranges of NH trilinear parameters by considering vacuum stability and observed properties of Higgs as the determining criteria.
hep-phJHEP(2017)·13 citations
13*
Observables for possible QGP signatures in central pp collisions
Michelangelo L. Mangano🇨🇭 · Benjamin Nachman🇺🇸
Proton-proton (pp) data show collective effects, such as long-range azimuthal correlations and strangeness enhancement, which are similar to phenomenology observed in heavy ion collisions. Using simulations with and without explicit existing models of collective effects, we explore new ways to probe pp collisions at high multiplicity, in order to suggest measurements that could help identify the similarities and differences between large- and small-scale collective effects. In particular, we focus on the properties of jets produced in ultra-central pp collisions in association with a Z boson. We consider observables such as jet energy loss and jet shapes, which could point to the possible existence of an underlying quark-gluon plasma, or other new dynamical effects related to the presence of large hadronic densities.
hep-phhep-exnucl-exnucl-thEPJC(2018)·30 citations
14*
Positivity of the real part of the forward scattering amplitude
André Martin🇨🇭 · Tai Tsun Wu🇺🇸
We prove the general theorem that the real part of the forward two-body scattering amplitude is positive at sufficiently high energies if, above a certain energy, the total cross section increases monotonically to infinity at infinite energy.
hep-phPRD(2018)·7 citations
15*
An upper limit on fermion mass spectrum in non-Hermitian models and its implications for studying of dark matter
V. N. Rodionov🇷🇺 · A. M. Mandel🇷🇺
The paper formulates a principal positions of non-Hermitian models with $γ_{5}$ -mass extensions, which often be ignored in some investigations for this subject. In fact in this case Hamiltonians contain not only Hermitian masses $m_{1}$ , but also contribution from anti-Hermitian components of fermion masses $m_{2}$ . Main misunderstanding a number of papers is consist in using of this model for any values of fermion masses for fixed values of $m_{1}$ and $m_{2}$ . However the basis appearing of two parameters masses may be undertaken a simple estimation for determination maximal permissible value of fermion mass $M = m_{1}^{2} /2 m_{2}$ which may be used for this model. Easy to see that $M$ becomes infinite and hence experimentally does not observable only in Dirac's limit, when the non-Hermitian mass fully is disappearing. In particular the equality $m_{1} = m_{2}$ can be realized only in two cases when $m_{1} = m_{2} = 0$ and $m_{1} = m_{2} = 2 M$ . Moreover in the second case the question is about the possibility existence a number of new fermions masses which are equal to the masses of particles Standard Model(SM) but when they have the non-Hermitian characteristics. In this case the paradox of the "two masses" takes place and its solution may be done only in suggested model with a maximal mass. Appearing particles can be considered as some new particles arising beyond SM. The unusual properties of these particles allow also to consider their as possible candidates in structure of dark matter.
hep-ph8 citations
16*
Gauge leptoquark as the origin of B-physics anomalies
Luca Di Luzio🇬🇧 · Admir Greljo🇨🇭 · Marco Nardecchia🇨🇭
The vector leptoquark representation, $U_{μ} = (3, 1, 2/3)$ , was recently identified as an exceptional single mediator model to address experimental hints on lepton flavour universality violation in semileptonic $B$ -meson decays, both in neutral ( $b \to s μμ$ ) and charged ( $b \to c τ ν$ ) current processes. Nonetheless, it is well-known that massive vectors crave an ultraviolet (UV) completion. We present the first full-fledged UV complete and calculable gauge model which incorporates this scenario while remaining in agreement with all other indirect flavour and electroweak precision measurements, as well as, direct searches at high- $p_{T}$ . The model is based on a new non-abelian gauge group spontaneously broken at the TeV scale, and a specific flavour structure suppressing flavour violation in $Δ F = 2$ processes while inducing sizeable semileptonic transitions.
hep-phhep-exPRD(2017)·338 citations
17*
LHC Run I Bounds on Minimal Lepton Flavour Violation in Type-III See-saw: A Case Study
Nuno Rosa Agostinho🇪🇸 · O.J.P.Eboli🇧🇷 · M.C.Gonzalez-Garcia🇪🇸
We study the bounds on minimal lepton flavour violation in the context of Type-III see-saw imposed by LHC Run I search for events which contain two charged leptons (either electron or muons of equal or opposite sign), two jets from a hadronically decaying $W$ boson and large missing transverse momentum. In this scenario the flavour structure of the couplings of the triplet fermions to the Standard Model leptons can be reconstructed from the neutrino mass matrix and lepton number violation is very suppressed. We find that using the information on charge and flavour of the leptons in the above final state it is possible to unambiguously rule out this scenario with triplet masses lighter than 300 GeV at 95% CL. The same analysis allows to exclude triplet masses masses up to 480 GeV at 95% CL for normal ordering of neutrino masses and specific values of a Majorana CP phase currently undetermined by neutrino physics.
hep-phJHEP(2017)·8 citations
18*
Nucleon Axial Radius and Muonic Hydrogen - A New Analysis and Review
Richard J. Hill🇺🇸 · Peter Kammel🇺🇸 · William J. Marciano🇺🇸 · Alberto Sirlin🇺🇸
Weak capture in muonic hydrogen ( $μ$ H) as a probe of the chiral properties and nucleon structure predictions of Quantum Chromodynamics (QCD) is reviewed. A recent determination of the axial-vector charge radius squared, $r_{A}^{2} (z exp.) = 0.46 (22) fm^{2}$ , from a model independent $z$ expansion analysis of neutrino-nucleon scattering data is employed in conjunction with the MuCap measurement of the singlet muonic hydrogen capture rate, $Λ_{singlet}^{MuCap} = 715.6 (7.4) s^{- 1}$ , to update the induced pseudoscalar nucleon coupling: $g ˉ_{P}^{MuCap} = 8.23 (83)$ derived from experiment, and $g ˉ_{P}^{theory} = 8.25 (25)$ predicted by chiral perturbation theory. Accounting for correlated errors this implies $g ˉ_{P}^{theory} / g ˉ_{P}^{MuCap} = 1.00 (8)$ , confirming theory at the 8% level. If instead, the predicted expression for $g ˉ_{P}^{theory}$ is employed as input, then the capture rate alone determines $r_{A}^{2} (μ H) = 0.46 (24) fm^{2}$ , or together with the independent $z$ expansion neutrino scattering results, a weighted average $r_{A}^{2} (ave.) = 0.46 (16) fm^{2}$ . Sources of theoretical uncertainty are critically examined and potential experimental improvements are described that can reduce the capture rate error by about a factor of 3. Muonic hydrogen can thus provide a precise and independent $r_{A}^{2}$ value which may be compared with other determinations, such as ongoing lattice gauge theory calculations. The importance of an improved $r_{A}^{2}$ determination for phenomenology is illustrated by considering the impact on critical neutrino-nucleus cross sections at neutrino oscillation experiments.
hep-phhep-latnucl-exnucl-thRept.Prog.Phys.(2018)·85 citations
19*
Probing axions with neutron star inspirals and other stellar processes
Anson Hook🇺🇸 · Junwu Huang🇨🇦
In certain models of a QCD axion, finite density corrections to the axion potential can result in the axion being sourced by large dense objects. There are a variety of ways to test this phenomenon, but perhaps the most surprising effect is that the axion can mediate forces between neutron stars that can be as strong as gravity. These forces can be attractive or repulsive and their presence can be detected by Advanced LIGO observations of neutron star inspirals. By a numerical coincidence, axion forces between neutron stars with gravitational strength naturally have an associated length scale of tens of kilometers or longer, similar to that of a neutron star. Future observations of neutron star mergers in Advanced LIGO can probe many orders of magnitude of axion parameter space. Because the axion is only sourced by large dense objects, the axion force evades fifth force constraints. We also outline several other ways to probe this phenomenon using electromagnetic signals associated with compact objects.
hep-phgr-qcJHEP(2018)·199 citations
20*
Determination of electric dipole transitions in heavy quarkonia using potential non-relativistic QCD
Jorge Segovia🇩🇪 · Sebastian Steinbeißer🇩🇪
The electric dipole transitions $χ_{b J} (1 P) \to γ Υ (1 S)$ with $J = 0, 1, 2$ and $h_{b} (1 P) \to γ η_{b} (1 S)$ are computed using the weak-coupling version of a low-energy effective field theory named potential non-relativistic QCD (pNRQCD). In order to improve convergence and thus give firm predictions for the studied reactions, the full static potential is incorporated into the leading order Hamiltonian; moreover, we must handle properly renormalon effects and re-summation of large logarithms. The precision we reach is $k_{γ}^{3} / (m v)^{2} \times O (v^{2})$ , where $k_{γ}$ is the photon energy, $m$ is the mass of the heavy quark and $v$ its velocity. Our analysis separates those relativistic contributions that account for the electromagnetic interaction terms in the pNRQCD Lagrangian which are $v^{2}$ suppressed and those that account for wave function corrections of relative order $v^{2}$ . Among the last ones, corrections from $1/ m$ and $1/ m^{2}$ potentials are computed, but not those coming from higher Fock states since they demand non-perturbative input and are $Λ_{QCD}^{2} / (m v)^{2}$ or $Λ_{QCD}^{3} / (m^{3} v^{4})$ suppressed, at least, in the strict weak coupling regime. These proceedings are based on the forthcoming publication \cite{steinbeisser}
hep-phhep-exhep-latnucl-thJ.Phys.Conf.Ser.(2018)·1 citation
21*
Transverse Vetoes with Rapidity Cutoff in SCET
Andrew Hornig🇺🇸 · Daekyoung Kang🇺🇸 · Yiannis Makris🇺🇸 · Thomas Mehen🇺🇸
We consider di-jet production in hadron collisions where a transverse veto is imposed on radiation for (pseudo-)rapidities in the central region only, where this central region is defined with rapidity cutoff. For the case where the transverse measurement (e.g., transverse energy or min $p_{T}$ for jet veto) is parametrically larger relative to the typical transverse momentum beyond the cutoff, the cross section is insensitive to the cutoff parameter and is factorized in terms of collinear and soft degrees of freedom. The virtuality for these degrees of freedom is set by the transverse measurement, as in typical transverse-momentum dependent observables such as Drell-Yan, Higgs production, and the event shape broadening. This paper focuses on the other region, where the typical transverse momentum below and beyond the cutoff is of similar size. In this region the rapidity cutoff further resolves soft radiation into (u)soft and soft-collinear radiation with different rapidities but identical virtuality. This gives rise to rapidity logarithms of the rapidity cutoff parameter which we resum using renormalization group methods. We factorize the cross section in this region in terms of soft and collinear functions in the framework of soft-collinear effective theory, then further refactorize the soft function as a convolution of the (u)soft and soft-collinear functions. All these functions are calculated at one-loop order. As an example, we calculate a differential cross section for a specific partonic channel, $q q^{'} \to q q^{'}$ , for the jet shape angularities and show that the refactorization allows us to resum the rapidity logarithms and significantly reduce theoretical uncertainties in the jet shape spectrum.
hep-phJHEP(2017)·24 citations
22*
The NLO electroweak effects on the Higgs production in association with bottom quark pair at the LHC
Yu Zhang🇨🇳
The dominant contribution to the Higgs production in association with bottom quark pair at the LHC is gluon-gluon fusion parton subprocess. We present a complete calculation of the next-to-leading order (NLO) electroweak (EW) corrections to this channel. The other small contributions with quarks in the initial state are calculated at tree level. We find that the NLO EW corrections can suppress the leading order (LO) contributions significantly.
hep-phPRD(2017)·12 citations
23*
Coulomb-type interaction under Lorentz symmetry breaking effects
R. L. L. Vitoria🇧🇷 · H. Belich🇧🇷 · K. Bakke🇧🇷
Based on models of confinement of quarks, we analyse a relativistic scalar particle subject to a scalar potential proportional to the inverse of the radial distance and under the effects of the violation of the Lorentz symmetry. We show that the effects of the Lorentz symmetry breaking can induced a harmonic-type potential. Then, we solve the Klein-Gordon equation analytically and discuss the influence of the background of the violation of the Lorentz symmetry on the relativistic energy levels.
hep-phhep-thquant-phAdv.High Energy Phys.(2017)·35 citations
24*
Searching for a dark photon: Project of the experiment at VEPP-3
B. Wojtsekhowski🇺🇸 · G.N. Baranov🇷🇺 · M.F. Blinov🇷🇺 · E.B. Levichev🇷🇺 · S.I. Mishnev🇷🇺 · D.M. Nikolenko🇷🇺 · I.A. Rachek🇷🇺 · Yu.V. Shestakov🇷🇺 · Yu.A. Tikhonov🇷🇺 · D.K. Toporkov🇺🇸 · J.P. Alexander🇺🇸 · M. Battaglieri🇮🇹 and 8 other authors
We propose an experiment to search for a new gauge boson A' in $e^{+} e^{-}$ annihilation by means of a positron beam incident on a gas hydrogen target internal to the bypass at the VEPP-3 storage ring. The search method is based on a missing mass spectra in the reaction $e^{+} e^{-} \to γ$ A'. It allows observation of the A' signal independently of its decay modes and life time. The projected result of this experiment corresponds to an upper limit on the square of the coupling constant $ε^{2} = 3 \cdot 1 0^{- 8}$ with a signal-to-noise ratio of two to one at an A' mass of 5-20 MeV.
↳ hep-exhep-phphysics.ins-detJINST(2018)·28 citations
25*
Gravitational leptogenesis in Natural Inflation
Alexandros Papageorgiou🇺🇸 · Marco Peloso🇺🇸
We compute the gravitational leptogenesis generated from the parity-violating gravitational waves sourced by an abelian gauge field coupled to a pseudo-scalar inflation. We show that, once the CMB bound on the tensor-to-scalar ratio is enforced, the lepton asymmetry produced by this mechanism during inflation is too small to account for the observed baryon asymmetry of the universe, irrespectively of the inflaton potential, the strength of its coupling to the gauge field, and the details of reheating.
↳ astro-ph.COhep-phhep-thJCAP(2017)·24 citations
26*
From Strangeness Enhancement to Quark-Gluon Plasma Discovery
Peter Koch🇩🇪 · Berndt Müller🇺🇸 · Johann Rafelski (Arizona)🇺🇸
This is a short survey of signatures and characteristics of the quark-gluon plasma in the light of experimental results that have been obtained over the past three decades. In particular, we present an in-depth discussion of the strangeness observable, including a chronology of the experimental effort to detect QGP at CERN-SPS, BNL-RHIC, and CERN-LHC.
↳ nucl-thhep-phInt.J.Mod.Phys.A(2017)·61 citations
27*
Freezeout systematics due to the hadron spectrum
Sandeep Chatterjee🇵🇱 · Debadeepti Mishra🇮🇳 · Bedangadas Mohanty🇮🇳 · Subhasis Samanta🇮🇳
We investigate systematics of the freezeout surface in heavy ion collisions due to the hadron spectrum. The role of suspected resonance states that are yet to be confirmed experimentally in identifying the freezeout surface has been investigated. We have studied two different freezeout schemes - unified freezeout scheme where all hadrons are assumed to freezeout at the same thermal state and a flavor dependent sequential freezeout scheme with different freezeout thermal states for hadrons with or without valence strange quarks. The data of mean hadron yields as well as scaled variance of net proton and net charge distributions have been analysed. We find the freezeout temperature $T$ to drop by $\sim 5%$ while the dimensionless freezeout parameters $μ_{B} / T$ and $V T^{3}$ ( $μ_{B}$ and $V$ are the baryon chemical potential and the volume at freezeout respectively) are insensitive to the systematics of the input hadron spectrum. The observed hint of flavor hierarchy in $T$ and $V T^{3}$ with only confirmed resonances survives the systematics of the hadron spectrum. It is more prominent between $s_{N N} \sim 10 - 100$ GeV where the maximum hierarchy in $T \sim 10%$ and $V T^{3} \sim 40%$ . However, the uncertainties in the thermal parameters due to the systematics of the hadron spectrum and their decay properties do not allow us to make a quantitative estimate of the flavor hierarchy yet.
↳ nucl-thhep-lathep-phnucl-exPRC(2017)·39 citations
28*
Gravitational Effective Action at Second Order in Curvature and Gravitational Waves
Xavier Calmet🇬🇧 · Salvatore Capozziello🇮🇹 · Daniel Pryer🇬🇧
We consider the full effective theory for quantum gravity at second order in curvature including non-local terms. We show that the theory contains two new degrees of freedom beyond the massless graviton: namely a massive spin-2 ghost and a massive scalar field. Furthermore, we show that it is impossible to fine-tune the parameters of the effective action to eliminate completely the classical spin-2 ghost because of the non-local terms in the effective action. Being a classical field, it is not clear anyway that this ghost is problematic. It simply implies a repulsive contribution to Newton's potential. We then consider how to extract the parameters of the effective action and show that it is possible to measure, at least in principle, the parameters of the local terms independently of each other using a combination of observations of gravitational waves and measurements performed by pendulum type experiments searching for deviations of Newton's potential.
↳ hep-thgr-qchep-phEPJC(2017)·31 citations
29*
Contribution of Kaon component in viscosity and conductivity of hadronic medium
Mahfuzur Rahaman🇧🇷 · Snigdha Ghosh🇮🇳 · Sabyasachi Ghosh🇮🇳 · Sourav Sarkar🇮🇳 · Jan-e Alam🇮🇳
The two-point correlation functions of kaonic viscous stress tensors and electro-magnetic currents have been calculated respectively to estimate the contributions of the strange sector in the shear viscosity and electrical conductivity of hadronic medium. In the one-loop correlators, kaon propagators contain a non-zero thermal width that leads to non-divergent values of transport coefficients. With the help of effective Lagrangian densities of strange hadrons, we have calculated in-medium self-energy of kaon for different possible mesonic loops, whose imaginary part provide the estimation of kaon thermal width. It is observed that near the quark-hadron transition temperature, the contribution of kaons to shear viscosity is larger and increases faster with temperature than pionic contribution. In case of electrical conductivity the trend due kaon component appears to be opposite in nature with respect to pion component.
↳ nucl-thhep-phPRC(2018)·5 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.