HEP Phenomenology·hep-ph

Mon·Dec 4, 2017Monday·December 4, 2017

31 papers—21 primary·10 cross-listed·reconstructed*

01*
Strongly Interacting Matter Phase Diagram in the presence of Magnetic Fields in an Extended Effective Lagrangian Approach with Explicit Chiral Symmetry Breaking Interactions
J. Moreira🇵🇹 · J. Morais🇵🇹 · B. Hiller🇵🇹 · A. A. Osipov🇷🇺 · A. H. Blin🇵🇹
Extensions of the NJL model which go beyond the original 4-quark interaction, which drives the dynamical mass generation, have proven to be quite successful in describing low energy hadronic phenomenology. The inclusion of 8-quark interaction terms solved a metastability problem of the effective potential introduced by the inclusion of the 6-quark 't Hooft determinant term in the 3-flavor version of the model (needed to eliminate the unwanted U(1) axial symmetry) . This model, that has proven to be quite powerful and feature-rich, has been expanded to include all the spin-0 terms, without and with explicit chiral symmetry breaking, which are of the same order as the 't Hooft flavor determinant in a 1/Nc expansion resulting in an unprecedented success in reproducing the low lying scalar and pseudoscalar meson spectra. This success can be seen as a result of the inclusion of the full chiral symmetry breaking pattern. The two critical endpoints which are obtained in the temperature/chemical potential phase diagram are shifted to lower chemical potential and higher temperature when the effect of magnetic field is taken into account. For the studied magnetic field strengths (in the range $eH = 0 - 0.4 G e V^{2}$ ) no significant extra transitions are seen to appear.
hep-phPoS(2018)·0 citations
02*
Electron Flavored Dark Matter
Wei Chao🇨🇳 · Huai-Ke Guo🇨🇳 · Hao-Lin Li🇺🇸 · Jing Shu🇨🇳
In this paper we investigate the phenomenology of the electron flavored Dirac dark matter with two types of portal interactions. We analyze constraints from the electron magnetic moment anomaly, LHC searches of singly charged scalar, dark matter relic abundance as well as direct and indirect detections. Our study shows that the available parameter space is quite constrained, but there are parameter space that is compatible with the current data. We further show that the DAMPE cosmic ray electron excess, which indicates cosmic ray excess at around 1.5 TeV, can be interpreted as the annihilation of dark matter into electron positron pairs in this model.
hep-phPLB(2018)·48 citations
03*
The pion holographic wavefunction with dynamical spin effects
Mohammad Ahmady🇨🇦 · Farrukh Chishtie🇨🇦 · Ruben Sandapen🇨🇦
We report that the inclusion of dynamical spin effects in the pion holographic light-front wavefunction leads to a remarkable improvement in describing pion observables (pion mean charge radius, decay constant, spacelike electromagnetic form factor) without the need to invoke higher Fock state contributions and/or a special AdS/QCD mass scale for the pion.
hep-phPoS(2018)·0 citations
04*
Recent advances on chiral partners and patterns
Angel Gómez Nicola🇪🇸 · Jacobo Ruiz de Elvira🇨🇭 · Silvia Ferreres-Solé🇸🇪 · Andrea Vioque-Rodríguez🇪🇸
We review recent results on chiral $S U (2)_{L} \times S U (2)_{R} \approx O (4)$ and $U (1)_{A}$ symmetry restoration in QCD. In particular, we discuss how Ward Identities allow one to derive general results on partner degeneration, which shed light on the distinction between the $O (4)$ and $O (4) \times U (1)_{A}$ patterns of the chiral transition. For that purpose, susceptibilities associated with the $O (4)$ and $U (1)_{A}$ symmetries are studied. From this analysis we conclude that in the ideal regime of exact $O (4)$ restoration (formally achieved in the limit of two massless flavours), $U (1)_{A}$ partners degenerate as well. We also discuss the role of the thermal $f_{0} (500)$ state to describe thermodynamic observables sensitive to chiral restoration, such as the scalar susceptibility. We pay special attention to the consistency of our results with recent lattice analysis.
hep-phPoS(2018)·0 citations
05*
Free Energy of a Large- $N$ Pion Gas and Chiral Symmetry Restoration
Santiago Cortés🇨🇴 · Ángel Gómez Nicola🇪🇸 · John Morales🇨🇴
We study thermal properties of a large-N massless pion gas using a low-energy QCD approach given by an $O (N + 1) / O (N)$ Nonlinear Sigma Model. We build diagrammatically the associated finite free energy to $O (T M^{3})$ in the pion mass expansion through an effective vertex that considers all the contributions coming from closed diagrams. Subsequently, we calculate finite order parameters such as the quark condensate and its respective derivative, i.e., the scalar susceptibility, in the chiral limit, along with their associated critical exponents. These results are compared with our previous unitarized scattering analyses for the chiral transition universality class, thus showing a reasonable agreement both with lattice simulations and these resonant studies.
hep-phPoS(2018)·0 citations
06*
Decay angular distributions of $K^{*}$ and $D^{*}$ mesons as a tool for the dynamics of open strange and charm production
Sang-Ho Kim🇰🇷 · Yongseok Oh🇰🇷 · Alexander I. Titov🇷🇺
We analyze decay spin-density matrix elements of $K^{*}$ and $D^{*}$ vector mesons and find that the corresponding vector meson decay distributions are sensitive to the production mechanisms. This suggests that the measurement of these quantities can be used to unravel the production mechanisms.
hep-phPhys.Part.Nucl.Lett.(2018)·0 citations
07*
AdS/QCD Modified Soft Wall Model and Light Meson Spectra
Santiago Cortés🇨🇴 · Miguel Ángel Martín Contreras🇨🇴 · José Rolando Roldán🇨🇴
We analyze here the mass spectrum of light vector and scalar mesons applying a novel approach where a modified soft wall model that includes a UV-cutoff at a finite $z$ -position in the AdS space is used, thus introducing an extra energy scale. For this model, we found that the masses for the scalar and vector spectra are well fitted within $δ_{R M S} = 7.64%$ for these states, with non-linear trajectories given by two common parameters, the UV locus $z_{0}$ and the quadratic dilaton profile slope $κ$ . We also conclude that in this model, the $f_{0} (500)$ scalar resonance cannot be fitted holographycally as a $q q$ state since we cannot find a trajectory that include this pole. This result is in agreement with the most recent phenomenological and theoretical methods.
hep-phPoS(2018)·0 citations
08*
Gravitational waves from phase transition in split NMSSM
S.V.Demidov🇷🇺 · D.S.Gorbunov🇷🇺 · D.V.Kirpichnikov🇷🇺
We discuss gravitational wave signal from the strongly first order electroweak phase transition in the split NMSSM. We find that for sets of parameters predicting successful electroweak baryogenesis the gravitational wave signal can be within the reach of future experiments LISA, BBO and Ultimate DECIGO.
hep-phPLB(2018)·50 citations
09*
Radiative effects in deep virtual Compton scattering
Igor Akushevich🇺🇸 · Alexander Ilyichev🇧🇾
Radiative corrections to the cross sections of photon electroproduction and the single spin asymmetries induced by the interference between the Bethe Heitler and deep virtual Compton scattering amplitudes are calculated within the leading log approximation. The deep virtual Compton scattering amplitude is presented in the Belitsky, Müller, and Kirchner approximation for the polarized initial particles. The Fortran code for estimation of the radiative effects in a given kinematic point and Monte Carlo generator for simulation of one or two photons are developed. Numerical results are performed for beam-spin asymmetries in kinematical conditions of current experiments in the Jefferson Laboratory.
hep-phPRD(2018)·8 citations
10*
Merging High Energy with Soft and Collinear Logarithms using HEJ and PYTHIA
Jeppe R. Andersen🇬🇧 · Helen M. Brooks🇦🇺 · Leif Lönnblad🇸🇪
We present a method to combine the all-order treatment of the High Energy Jets exclusive partonic Monte Carlo (HEJ) with the parton shower of Pythia8, while retaining the logarithmic accuracy of both. This procedure enables the generation of fully realistic and hadronised events with HEJ. Furthermore, the combination of the two all-order treatments leads to improvements in the quality of the description of observables, in particular for regions with disparate transverse scales.
hep-phhep-exJHEP(2018)·11 citations
11*
Locating the critical end point using the linear sigma model coupled to quarks
A. Ayala🇲🇽 · J. A. Flores🇲🇽 · L. A. Hernandez🇲🇽 · S. Hernandez-Ortiz🇲🇽
We use the linear sigma model coupled to quarks to compute the effective potential beyond the mean field approximation, including the contribution of the ring diagrams at finite temperature and baryon density. We determine the model couplings and use them to study the phase diagram in the baryon chemical potential-temperature plane and to locate the Critical End Point.
hep-phnucl-thEPJ Web Conf.(2018)·4 citations
12*
CP-odd Higgs Boson Production in $e γ$ Collisions
Ken Sasaki🇯🇵 · Tsuneo Uematsu🇯🇵
We investigate the CP-odd Higgs boson production via two-photon processes in $e γ$ collisions. The CP-odd Higgs boson, which we denote as $A^{0}$ , is expected to appear in the Two-Higgs Doublet Models (2HDM) as a minimal extension of Higgs sector for which the Minimal Supersymmetric Standard Model (MSSM) is a special case. The scattering amplitude for $e γ \to e A^{0}$ is evaluated at the electroweak one-loop level. The dominant contribution comes only from top-quark loops when $A^{0}$ boson is rather light and $tan β$ is not large. There are no contributions from the $W$ -boson and $Z$ -boson loops nor from the scalar top-quark (stop) loops. The differential cross section for the $A^{0}$ production is analysed.
hep-phPLB(2018)·11 citations
13*
Calculation of the ratios and absolute rates of the $Ξ_{b}^{-} \to π^{-} (D_{s}^{-}) Ξ_{c}^{0} (2790) (Ξ_{c}^{0} (2815))$ and $Ξ_{b}^{-} \to ν ˉ_{l} l Ξ_{c}^{0} (2790) (Ξ_{c}^{0} (2815))$ decays
R. Pavao🇪🇸 · W-H Liang🇨🇳 · J. Nieves🇪🇸 · E. Oset🇪🇸
In this work we calculate the ratios of rates of the $Ξ_{b}$ nonleptonic and semileptonic decays into the $Ξ_{c}$ (2790) and $Ξ_{c}$ (2815) ( $Ξ_{c}^{*}$ ) resonances. These resonances are dynamically generated from the pseudoscalar-baryon and vector-baryon interactions, whose mixing is done using the chiral Weinberg-Tomozawa (WT) meson-baryon interaction extended to four flavors. The first part of the decay is a weak decay that we analyze through their quark constituents where it is noted that only the heavy quarks ( $b$ and $c$ ) participate in the interaction, leaving the light pair ( $d s$ ) as spectators. This first decay then produces a meson-baryon pair that creates the $Ξ_{c}^{*}$ through the WT interaction. We then proceed to calculate the decay rates to $Ξ_{c}$ (2790) and $Ξ_{c}$ (2815) for both the nonleptonic and semileptonic cases and then calculate the ratios between them. We do this calculation nonrelativistically and fully relativistically and notice that, even though both approaches yield somewhat different results in the rates, the ratios are very similar (difference on the order of 1\%) in both cases. The absolute values of the decay rates are also successfully calculated by obtaining the rates between our decays and $Λ_{b} \to π (D_{s}) Λ_{c} (2595) (Λ_{c} (2625))$ and $Λ_{b} \to ν ˉ_{l} l Λ_{c} (2595) (Λ_{c} (2625))$ for which there are experimental results, since the momentum transfer is similar such we can cancel out the influence of the quark wave functions in the ratios.
hep-phPoS(2018)·0 citations
14*
Probe $C P$ -violating $H γ γ$ coupling through interferometry
Xia Wan🇨🇳 · You-Kai Wang🇨🇳
The diphoton invariant mass distribution of interference between $g g \to H \to γ γ$ and $g g \to γ γ$ is almost antisymmetric around the Higgs mass $M_{H}$ . We propose a new observable $A_{int}$ to quantify this effect, which is a ratio of a sign-reversed integral around $M_{H}$ ( e.g. $\int_{M_{H} - 5 \mbox G e V}^{M_{H}} - \int_{M_{H}}^{M_{H} + 5 \mbox G e V}$ ) and the cross section of the Higgs signal. We study $A_{int}$ both in Standard Model (SM) and new physics with various $C P$ -violating $H γ γ$ couplings. The $A_{int}$ in SM could reach a value of $10%$ , while for $C P$ -violating $H γ γ$ couplings $A_{int}$ could range from $10%$ to $- 10%$ , which is probable to be detected in HL-LHC experiment. The $A_{int}$ with both $C P$ -violating $H γ γ$ and $H g g$ couplings are also studied and its value range is further extended.
hep-phCPC(2019)·2 citations
15*
Elastic proton-proton scattering at 13 TeV
V.A. Khoze🇬🇧 · A.D. Martin🇬🇧 · M.G. Ryskin🇬🇧
The predictions of a model which was tuned in 2013 to describe the elastic and diffractive $pp$ - and/or $p p ˉ$ -data at collider energies up to 7 TeV are compared with the new 13 TeV TOTEM results. The possibility of an odd-signature Odderon exchange contribution is discussed.
hep-phPRD(2018)·56 citations
16*
$Ω_{c}$ excited states within a $SU (6)_{lsf} \times$ HQSS model
J. Nieves🇪🇸 · R. Pavao🇪🇸 · L. Tolos🇩🇪
We have reviewed the renormalization procedure used in the unitarized coupled-channel model of Phys. Rev. D85 114032 (2012), and its impact in the $C = 1$ , $S = - 2$ , and $I = 0$ sector, where five $Ω_{c}^{(*)}$ states have been recently observed by the LHCb Collaboration. The meson-baryon interactions used in the model are consistent with both chiral and heavy-quark spin symmetries and lead to a successful description of the observed lowest-lying odd parity resonances $Λ_{c} (2595)$ and $Λ_{c} (2625)$ , and $Λ_{b} (5912)$ and $Λ_{b} (5920)$ resonances. We show that some (probably at least three) of the states observed by LHCb will also have odd parity and spins $J = 1/2$ and $J = 3/2$ , belonging two of them to the same $SU (6)_{light - spin - flavor} \times$ HQSS multiplets that the latter strangenessless heavy $- Λ$ baryons.
hep-phhep-exnucl-thEPJC(2018)·41 citations
17*
Exploring collider aspects of a neutrinophilic Higgs doublet model in multilepton channels
Katri Huitu🇫🇮 · Timo J. Kärkkäinen🇫🇮 · Subhadeep Mondal🇫🇮 · Santosh Kumar Rai🇮🇳
We consider a neutrinophilic Higgs scenario where the Standard Model is extended by one additional Higgs doublet and three generations of singlet right-handed Majorana neutrinos. Light neutrino masses are generated through mixing with the heavy neutrinos via Type-I seesaw mechanism when the neutrinophilic Higgs gets a vacuum expectation value (VEV). The Dirac neutrino Yukawa coupling in this scenario can be sizable compared to those in the canonical Type-I seesaw mechanism owing to the small neutrinophilic Higgs VEV giving rise to interesting phenomenological consequences. We have explored various signal regions likely to provide a hint of such a scenario at the LHC as well as at future $e^{+} e^{-}$ colliders. We have also highlighted the consequences of light neutrino mass hierarchies in collider phenomenology that can complement the findings of neutrino oscillation experiments.
hep-phPRD(2018)·14 citations
18*
Leptogenesis with TeV Scale $W_{R}$
Pei-Hong Gu🇨🇳 · Rabindra N. Mohapatra🇺🇸
Successful leptogenesis within the conventional TeV-scale left-right implementation of type-I seesaw has been shown to require that the mass of the right-handed $W_{R}^{\pm}$ boson should have a lower bound much above the reach of the Large Hadron Collider. This bound arises from the necessity to suppress the washout of lepton asymmetry due to $W_{R}^{\pm}$ -mediated $Δ L \neq = 0$ processes. We show that in an alternative quark seesaw realization of left-right symmetry, the above bound can be avoided. Lepton asymmetry in this model is generated not via the usual right-handed neutrino decay but rather via the decay of new heavy scalars producing an asymmetry in the $B - L$ carrying Higgs triplets responsible for type-II seesaw, whose subsequent decay leads to the lepton asymmetry. This result implies that any evidence for $W_{R}$ at the LHC 14 will point towards this alternative realization of left-right symmetry, which is also known to solve the strong CP problem.
hep-phPRD(2018)·7 citations
19*
Relativistic Corrections to Nonrelativistic Effective Field Theories
Mohammad Hossein Namjoo🇺🇸 · Alan H. Guth🇺🇸 · David I. Kaiser🇺🇸
In this paper we develop a formalism for studying the nonrelativistic limit of relativistic field theories in a systematic way. By introducing a simple, nonlocal field redefinition, we transform a given relativistic theory, describing a real, self-interacting scalar field, into an equivalent theory, describing a complex scalar field that encodes at each time both the original field and its conjugate momentum. Our low-energy effective theory incorporates relativistic corrections to the kinetic energy as well as the backreaction of fast-oscillating terms on the behavior of the dominant, slowly varying component of the field. Possible applications of our new approach include axion dark matter, though the methods developed here should be applicable to the low-energy limits of other field theories as well.
hep-phastro-ph.COhep-thPRD(2018)·88 citations
20*
$S U (4)$ -Ward identities for QCD with restored chiral symmetry
Vasily Sazonov🇦🇹
Lattice studies of QCD at temperatures above the chiral restoration and QCD with truncated low modes of the Dirac operator indicate approximate and explicit $S U (4)$ degeneracies in hadron spectra, respectively. At the same time, the QCD classical action and the path integral measure are not invariant under $S U (4)$ . Here we investigate $S U (4)$ transformations in the continuum limit by deriving corresponding Ward identities. We show that, if there is a gap in low-lying modes of the Dirac operator the obtained $S U (4)$ Ward identities are simplified and look like they would be if $S U (4)$ symmetry is preserved. Then, we discuss possible consequences for the quark matter at high temperatures.
hep-phhep-lathep-th0 citations
21*
Self-Destructing Dark Matter
Yuval Grossman🇺🇸 · Roni Harnik🇺🇸 · Ofri Telem🇺🇸 · Yue Zhang🇺🇸
We present Self-Destructing Dark Matter (SDDM), a new class of dark matter models which are detectable in large neutrino detectors. In this class of models, a component of dark matter can transition from a long-lived state to a short-lived one by scattering off of a nucleus or an electron in the Earth. The short-lived state then decays to Standard Model particles, generating a dark matter signal with a visible energy of order the dark matter mass rather than just its recoil. This leads to striking signals in large detectors with high energy thresholds. We present a few examples of models which exhibit self destruction, all inspired by bound state dynamics in the Standard Model. The models under consideration exhibit a rich phenomenology, possibly featuring events with one, two, or even three lepton pairs, each with a fixed invariant mass and a fixed energy, as well as non-trivial directional distributions. This motivates dedicated searches for dark matter in large underground detectors such as Super-K, Borexino, SNO+, and DUNE.
hep-phastro-ph.COhep-exJHEP(2019)·27 citations
22*
Dynamical violation of scale invariance and the dilaton in a cold Fermi gas
Gordon W. Semenoff🇨🇦 · Fei Zhou🇨🇦
We use the large N approximation to find an exotic phase of a cold, two-dimensional, N-component Fermi gas which exhibits dynamically broken approximate scale symmetry. We identify a particular weakly damped collective excitation as the dilaton, the pseudo-Goldstone boson associated with the broken approximate scale symmetry. We argue that the symmetry breaking phase is stable for a range of parameters of the theory and there is a fluctuation induced first order quantum phase transition between the normal and the scale symmetry breaking phases which can be driven by tuning the chemical potential. We find that the compressibility of the gas at its lower critical density is anomalously large, 2N times that of a perfect gas at the same density.
↳ cond-mat.quant-gashep-phhep-thPRL(2018)·5 citations
23*
Quantum gravity fluctuations flatten the Planck-scale Higgs potential
Astrid Eichhorn🇩🇪 · Yuta Hamada🇯🇵 · Johannes Lumma🇩🇪 · Masatoshi Yamada🇩🇪
We investigate asymptotic safety of a toy model of a singlet-scalar extension of the Higgs sector including two real scalar fields under the impact of quantum-gravity fluctuations. Employing functional renormalization group techniques, we search for fixed points of the system which provide a tentative ultraviolet completion of the system. We find that in a particular regime of the gravitational parameter space the canonically marginal and relevant couplings in the scalar sector -- including the mass parameters -- become irrelevant at the ultraviolet fixed point. The infrared potential for the two scalars that can be reached from that fixed point is fully predicted and features no free parameters. In the remainder of the gravitational parameter space, the values of the quartic couplings in our model are predicted. In light of these results, we discuss whether the singlet-scalar could be a dark-matter candidate. Furthermore, we highlight how "classical scale invariance" in the sense of a flat potential of the scalar sector at the Planck scale could arise as a consequence of asymptotic safety.
↳ hep-thgr-qchep-phPRD(2018)·130 citations
24*
ABJM quantum spectral curve and Mellin transform
R.N. Lee🇷🇺 · A.I. Onishchenko🇷🇺
The present techniques for the perturbative solution of quantum spectral curve problems in N=4 SYM and ABJM models are limited to the situation when the states quantum numbers are given explicitly as some integer numbers. These techniques are sufficient to recover full analytical structure of the conserved charges provided that we know a finite basis of functions in terms of which they could be written explicitly. It is known that in the case of N=4 SYM both the contributions of asymptotic Bethe ansatz and wrapping or finite size corrections are expressed in terms of the harmonic sums. However, in the case of ABJM model only the asymptotic contribution can still be written in the harmonic sums basis, while the wrapping corrections part can not. Moreover, the generalization of harmonic sums basis for this problem is not known. In this paper we present a Mellin space technique for the solution of multiloop Baxter equations, which is the main ingredient for the solution of corresponding quantum spectral problems, and provide explicit results for the solution of ABJM quantum spectral curve in the case of twist 1 operators in sl(2) sector for arbitrary spin values up to four loop order with explicit account for wrapping corrections. It is shown that the result for anomalous dimensions could be expressed in terms of harmonic sums decorated by the fourth root of unity factors, so that maximum transcendentality principle holds.
↳ hep-thhep-phJHEP(2018)·19 citations
25*
Hadronic light-by-light scattering amplitudes from lattice QCD versus dispersive sum rules
Antoine Gérardin🇩🇪 · Jeremy Green🇩🇪 · Oleksii Gryniuk🇩🇪 · Georg von Hippel🇩🇪 · Harvey B. Meyer🇩🇪 · Vladimir Pascalutsa🇩🇪 · Hartmut Wittig🇩🇪
The hadronic contribution to the eight forward amplitudes of light-by-light scattering ( $γ^{*} γ^{*} \to γ^{*} γ^{*}$ ) is computed in lattice QCD. Via dispersive sum rules, the amplitudes are compared to a model of the $γ^{*} γ^{*} \to hadrons$ cross sections in which the fusion process is described by hadronic resonances. Our results thus provide an important test for the model estimates of hadronic light-by-light scattering in the anomalous magnetic moment of the muon, $a_{μ}^{HLbL}$ . Using simple parametrizations of the resonance $M \to γ^{*} γ^{*}$ transition form factors, we determine the corresponding monopole and dipole masses by performing a global fit to all eight amplitudes. Together with a previous dedicated calculation of the $π^{0} \to γ^{*} γ^{*}$ transition form factor, our calculation provides valuable information for phenomenological estimates of $a_{μ}^{HLbL}$ . The presented calculations are performed in two-flavor QCD with pion masses extending down to 190\,MeV at two different lattice spacings. In addition to the fully connected Wick contractions, on two lattice ensembles we also compute the (2+2) disconnected class of diagrams, and find that their overall size is compatible with a parameter-free, large- $N$ inspired prediction, where $N$ is the number of colors. Motivated by this observation, we estimate in the same way the disconnected contribution to $a_{μ}^{HLbL}$ .
↳ hep-lathep-phPRD(2018)·36 citations
26*
Estimates for a DM $\to a \to γ$ 3.55 keV line in the radio lobes of Centaurus A
Nicholas Jennings🇬🇧
The origin of the 3.55 keV excess reported in various galaxies and galaxy clusters remains unknown. Non-observations of the line in dwarf spheroidal galaxies (dSphs) create tension with galaxy cluster observations when considering a direct Dark Matter (DM) $\to γ$ decay. This discrepancy could be explained by a DM $\to a \to γ$ decay, where the DM particles decay to axion-like particles (ALPs), which then convert to photons in a magnetic field. The 3.55 keV line from a decay to ALPs therefore has very different morphology from a direct decay to photons, as it would only appear in environments with substantial magnetic fields between the source and us. To test this hypothesis we consider targets where the line strength would be enhanced compared to the DM $\to γ$ model. The giant lobes of radio galaxies could represent good environments, having magnetic fields with strength $O (μ G)$ that extend for hundreds of kiloparsecs, and minimal X-ray background. In the case of Centaurus A, a large population of dSphs are associated with the galaxy, some of which are potentially in or behind its lobes. In this paper we estimate the flux of a 3.55 keV DM $\to a \to γ$ line from these sources, and compare it to the flux from the DM halo of Centaurus~A. We comment on the potential to detect such a signal with current satellites (such as XMM-Newton and Chandra) and future satellites (such as Athena).
↳ astro-ph.HEhep-ph1 citation
27*
Implications from GW170817 and I-Love-Q relations for relativistic hybrid stars
Vasileios Paschalidis🇺🇸 · Kent Yagi🇺🇸 · David Alvarez-Castillo🇷🇺 · David B. Blaschke🇷🇺 · Armen Sedrakian🇩🇪
Gravitational wave observations of GW170817 placed bounds on the tidal deformabilities of compact stars allowing one to probe equations of state for matter at supranuclear densities. Here we design new parametrizations for hybrid hadron-quark equations of state, that give rise to low-mass twin stars, and test them against GW170817. We find that GW170817 is consistent with the coalescence of a binary hybrid star--neutron star. We also test and find that the I-Love-Q relations for hybrid stars in the third family agree with those for purely hadronic and quark stars within $\sim 3%$ for both slowly and rapidly rotating configurations, implying that these relations can be used to perform equation-of-state independent tests of general relativity and to break degeneracies in gravitational waveforms for hybrid stars in the third family as well.
↳ astro-ph.HEgr-qchep-phnucl-thPRD(2018)·258 citations
28*
Intermediate mass black holes and dark matter at the Galactic center
Thomas Lacroix🇫🇷 · Joseph Silk🇫🇷
Could there be a large population of intermediate-mass black holes (IMBHs) formed in the early universe? Whether primordial or formed in Population III, these are likely to be very subdominant compared to the dark matter density, but could seed early dwarf galaxy/globular cluster and supermassive black hole formation. Via survival of dark matter density spikes, we show here that a centrally concentrated relic population of IMBHs, along with ambient dark matter, could account for the Fermi gamma-ray "excess" in the Galactic center because of dark matter particle annihilations.
↳ astro-ph.GAastro-ph.COastro-ph.HEhep-phApJL(2018)·15 citations
29*
Quantum Limitation to the Coherent Emission of Accelerated Charges
A. Angioi🇩🇪 · A. Di Piazza🇩🇪
Accelerated charges emit electromagnetic radiation. According to classical electrodynamics if the charges move along sufficiently close trajectories they emit coherently, i.e., their emitted energy scales quadratically with their number rather than linearly. By investigating the emission by a two-electron wave packet in the presence of an electromagnetic plane wave within strong-field QED, we show that quantum effects deteriorate the coherence predicted by classical electrodynamics even if the typical quantum nonlinearity parameter of the system is much smaller than unity. We explain this result by observing that coherence effects are also controlled by a new quantum parameter which relates the recoil undergone by the electron with the width of its wave packet in momentum space.
↳ quant-phhep-phPRL(2018)·24 citations
30*
Quantification of Chiral Magnetic Effect from Event-by-Event Anomalous-Viscous Fluid Mechanics
Shuzhe Shi🇺🇸 · Yin Jiang🇨🇳 · Elias Lilleskov🇺🇸 · Jinfeng Liao🇺🇸
Chiral Magnetic Effect (CME) is the macroscopic manifestation of the fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as anomalous transport current in hydrodynamic framework. Experimental observation of CME is of great interest and significant efforts have been made to look for its signals in heavy ion collisions. Encouraging evidence of CME-induced charge separation has been reported from both RHIC and LHC, albeit with ambiguity due to potential background contributions. Crucial for addressing such issue, is the need of quantitative predictions for both CME signal and the non-CME background consistently, with sophisticated modeling tool. In this contribution we report a recently developed Anomalous Viscous Fluid Dynamics (AVFD) framework, which simulates the evolution of fermion currents in QGP on top of the data-validated VISHNU bulk hydro evolution. In particular, this framework has been extended to event-by-event simulations with proper implementation of known flow-driven background contributions. We report quantitative results from such simulations and evaluate the implications for interpretations of current experimental measurements. Finally we give our prediction for the CME signal in upcoming isobaric collisions.
↳ nucl-thhep-phPoS(2018)·4 citations
31*
Fractal structure and non extensive statistics
Airton Deppman🇧🇷 · Eugenio Megias🇪🇸 · Debora P. Menezes🇧🇷 · Tobias Frederico🇧🇷
The role played by non extensive thermodynamics in physical systems has been under intense debate for the last decades. With many applications in several areas, the Tsallis statistics has been discussed in details in many works and triggered an interesting discussion on the most deep meaning of entropy and its role in complex systems. Some possible mechanisms that could give rise to non extensive statistics have been formulated along the last several years, in particular a fractal structure in thermodynamics functions was recently proposed as a possible origin for non extensive statistics in physical systems. In the present work we investigate the properties of such fractal thermodynamical system and propose a diagrammatic method for calculations of relevant quantities related to such system. It is shown that a system with the fractal structure described here presents temperature fluctuation following an Euler Gamma Function, in accordance with previous works that evidenced the connections between those fluctuations and Tsallis statistics. Finally, the fractal scale invariance is discussed in terms of the Callan-Symanzik Equation.
↳ cond-mat.stat-mechhep-phEntropy(2018)·31 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.