Mon·Apr 3, 2017Monday·April 3, 2017

1. 01*

   Minimally extended SILH

   Mikael Chala🇩🇪 · Gauthier Durieux🇩🇪 · Christophe Grojean🇩🇪 · Leonardo de Lima🇩🇪 · Oleksii Matsedonskyi🇩🇪

   Higgs boson compositeness is a phenomenologically viable scenario addressing the hierarchy problem. In minimal models, the Higgs boson is the only degree of freedom of the strong sector below the strong interaction scale. We present here the simplest extension of such a framework with an additional composite spin-zero singlet. To this end, we adopt an effective field theory approach and develop a set of rules to estimate the size of the various operator coefficients, relating them to the parameters of the strong sector and its structural features. As a result, we obtain the patterns of new interactions affecting both the new singlet and the Higgs boson's physics. We identify the characteristics of the singlet field which cause its effects on Higgs physics to dominate over the ones inherited from the composite nature of the Higgs boson. Our effective field theory construction is supported by comparisons with explicit UV models.

   hep-phJHEP(2017)·56 citations
2. 02*

   Search for more sensitive observables to charged scalars in $B\to D^{(\ast )}\tau {\nu }_{\tau }$ decays

   Lobsang Dhargyal🇮🇳

   It has been known that $B\to D^{(\ast )}\tau {\nu }_{\tau }$ are good observables in the search for the charged Higgs. The recent obervation of deviation from standard-model by almost 4$\sigma$ by Babar, Belle and LHCb in $R(D^{(\ast )})$ revived the interest in possible signal of presence of charged Higgs in these modes. But such a large deviation in the rates, where standard-model has tree level contribution, coming from a charged Higgs alone is highly unlikely. However these decay modes are good probes to search for small charged Higgs signal if we can construct sensitive observables in these modes. In this work we would like to propose four new observables which shows much more sensitivity to the presence of charged Higgs than the usual observables such as $A_{\lambda }^{D^{(\ast )}}$ and $A_{\theta }^{D^{(\ast )}}$. These four observable are (1) $\frac{1}{A_{\lambda }^D}$,\ (2) $Y_1(q^2)=\frac{A_{\theta }^D}{A_{\lambda }^D}$,\ (3) $Y_2(q^2)=\frac{d\Gamma (B\to D^{\ast }\tau {\nu }_{\tau })}{d{\Gamma }_D({\lambda }_{\tau }=+1/2)-d{\Gamma }_D({\lambda }_{\tau }=-1/2)}$ and (4) $Y_3(q^2)=(\frac{q^2}{m_{\tau }^2})(A_{\lambda }^D+1)\frac{1}{A_{\lambda }^D}$.

   hep-phLHEP(2019)·0 citations
3. 03*

   Soft Interactions in Herwig

   S. Gieseke🇩🇪 · P. Kirchgaeßer🇩🇪 · F. Loshaj🇩🇪

   We introduce a new model for soft interactions in the Monte Carlo event generator Herwig. We add a new model for the simulation of diffractive final states, based on the cluster hadronization model in Herwig. The soft component of the Multiple partonic interaction model is replaced by a refined model for soft gluon production. With these two components we are for the first time able to give a full simulation of minimum-bias events at hadron colliders. We briefly describe the models and present a few results obtained with it.

   hep-ph4 citations
4. 04*

   Study of open-charm $0^{+}$ states in unitarized chiral effective theory with one-loop potentials

   Meng-Lin Du🇩🇪 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪 · De-Liang Yao🇪🇸

   Chiral potentials are derived for the interactions between Goldstone bosons and pseudoscalar charmed mesons up to next-to-next-to-leading order in a covariant chiral effective field theory with explicit vector charmed-meson degrees of freedom. Using the extended-on-mass-shell scheme, we demonstrate that the ultraviolet divergences and the so-called power counting breaking terms can be properly absorbed by the low-energy constants of the chiral Lagrangians. We calculate the scattering lengths by unitarizing the one-loop potentials and fit them to the data extracted from lattice QCD. The obtained results are compared to the ones without an explicit contribution of vector charmed mesons given previously. It is found that the difference is negligible for $S$-wave scattering in the threshold region. This validates the use of $D^{\ast }$-less one-loop potentials in the study of the pertinent scattering lengths. We search for dynamically generated open-charm states with $J^P=0^{+}$ as poles of the $S$-matrix on various Riemann sheets. The trajectories of those poles for varying pion masses are presented as well.

   hep-phEPJC(2017)·59 citations
5. 05*

   Constraints on Two Higgs Doublet Model Parameters in the light of rare $B$-Decays

   Mureed Hussain🇵🇰 · Muhammad Usman🇵🇰 · Muhammad Ali Paracha🇵🇰 · Muhammad Jamil Aslam🇵🇰

   We established the allowed parameters of two-Higgs doublet model(2HDM) from flavor physics observables, precisely from rare $B$ meson decays. In our analysis most formidable constraints on the 2HDM parameters arise from the branching ratio of rare radiative $B$ meson decay i.e., $B\to X_s\gamma$. However, the constraints arising from the branching ratio of $B_s\to {\mu }^{+}{\mu }^{-}$ decay in $m_{H^{\pm }}-\tan \beta$ plane give $m_{H^{\pm }}>$ 80 GeV for the value of $\tan \beta \sim 2$, that is in agreement with large electron-positron collider (LEP) data. Furthermore, we also investigate the bounds on the $CP$-even $m_H$ and $CP$-odd $m_{A^0}$ Higgs boson not only from above mentioned physical observables, but also from the zero crossing of the forward-backward asymmetry of $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$ decay. Therefore, these bounds on parameters of the 2HDM will provides a fertile ground to test the 2HDM at current and future $B$-physics experiments.

   hep-phPRD(2017)·12 citations
6. 06*

   Quenching of Hadron Spectra in Heavy Ion Collisions at the LHC

   François Arleo🇫🇷

   The $p_{\perp }$ dependence of the nuclear modification factor $R_{\mathrm{AA}}$ measured in PbPb collisions at the LHC exhibits a universal shape, which can be very well reproduced in a simple energy loss model based on the BDMPS medium-induced gluon spectrum. The scaling is observed for various hadron species ($h^{\pm }$, $D$, $J/\psi$) in different centrality classes and at both colliding energies, $\sqrt{s}=2.76$ TeV and $\sqrt{s}=5.02$ TeV. Results indicate an 10-20% increase of the transport coefficient from $\sqrt{s}=2.76$ TeV to $\sqrt{s}=5.02$ TeV, consistent with that of particle multiplicity. Based on this model, a data-driven procedure is suggested, which allows for the determination of the first and second moments of the quenching weight without any prior knowledge of the latter.

   hep-phhep-exPRL(2017)·76 citations
7. 07*

   Double-Longitudinal Spin Asymmetry in Single-Inclusive Lepton Scattering at NLO

   Patriz Hinderer🇩🇪 · Marc Schlegel🇩🇪 · Werner Vogelsang🇩🇪

   We calculate the double-spin asymmetries $A_{\mathrm{LL}}$ for the processes $\ell N\to hX$ and $\ell N\to \mathrm{jet}X$ at next-to-leading order accuracy in perturbative QCD. We compare our theoretical results for $A_{\mathrm{LL}}$ to data from the SLAC E155 experiment, finding only partially satisfactory agreement. We conclude that measurements of $A_{\mathrm{LL}}$ and the relevant polarized and unpolarized cross sections should be performed at the present-day fixed-target lepton scattering experiments, as well as at a future electron ion collider, in order to verify our understanding of this process. We present predictions of the longitudinal double-spin asymmetries for these experiments.

   hep-phhep-exPRD(2017)·20 citations
8. 08*

   DPD sum rules in QCD

   Peter Plößl🇩🇪

   We review the DPD sum rules and establish their validity to all orders in QCD. This is done using a diagrammatic approach and light-front perturbation theory. In the process we furthermore investigate the QCD evolution of double parton distributions and obtain sum rules for $1\to 2$ splitting kernels in close analogy to the DPD sum rules themselves.

   hep-ph3 citations
9. 09*

   Solving the muon g-2 anomaly in deflected AMSB with messenger-matter interactions

   Fei Wang🇨🇳 · Wenyu Wang🇨🇳 · Jin Min Yang🇨🇳

   We proposed to introduce general messenger-matter interactions in the deflected anomaly mediated SUSY breaking scenario to explain the $g_{\mu }-2$ anomaly. Scenarios with complete or incomplete GUT multiplet messengers are discussed, respectively. The introduction of incomplete GUT mulitiplets can be advantageous in various aspects. We found that the $g_{\mu }-2$ anomaly can be solved in both scenarios under current constraints including the gluino mass bounds, while the scenarios with incomplete GUT representation messengers are more favored by the $g_{\mu }-2$ data. We also found that the gluino is upper bounded by about 2.5 TeV (2.0 TeV) in Scenario A and 3.0 TeV (2.7 TeV) in Scenario B if the generalized deflected AMSB scenarios are used to fully account for the $g_{\mu }-2$ anomaly at $3\sigma$ ($2\sigma$) level. Such a gluino should be accessible in the future LHC searches. Dark matter constraints, including DM relic density and direct detection bounds, favor the scenario B with incomplete GUT multiplets. Much of the allowed parameter space for the scenario B could be covered by the future DM direct detection experiments.

   hep-phPRD(2017)·21 citations
10. 10*

    Parton correlations effects in double parton distribution functions

    Matteo Rinaldi🇪🇸 · Sergio Scopetta🇮🇹 · Vicente Vento🇪🇸 · Marco Traini🇮🇹 · Federico Alberto Ceccopieri🇧🇪

    Double parton distribution functions (dPDFs), measurable in hadron-hadron collisions and encoding information on how partons inside a proton are correlated among each other, could represent a new tool to explore the three dimensional partonic structure of hadrons. In the present contribution, results of the calculations of dPFDs are presented. Phenomenological calculations of experimental observables, sensitive to dPDFs are also discussed showing how double parton correlations could be estimated in the next LHC run.

    hep-phnucl-th0 citations
11. 11*

    A Fermionic bi-Doublet Effective Field Theory for Dark Matter

    Dimitrios Karamitros🇬🇷

    We study an effective field theory which includes the Standard Model extended by a Dark Sector consisting of two fermionic $SU(2{)}_L$-doublets. A $Z_2$ parity guarantees that, after electroweak symmetry breaking, the lightest neutral particle is stable, acting as a WIMP. The dark sector interacts with the Higgs and gauge bosons through renormalizable and non-renormalizable $d=5$ operators. We find that a WIMP with a mass around the electroweak scale, i.e. accessible at the LHC, is consistent with collider and astrophysical data only when non-trivial magnetic dipole interactions with the gauge bosons exist.

    hep-phastro-ph.COPoS(2017)·0 citations
12. 12*

    Hard color singlet BFKL exchange and gaps between jets at the LHC

    Andreas Ekstedt🇸🇪 · Rikard Enberg🇸🇪 · Gunnar Ingelman🇸🇪

    We explore the perturbative QCD dynamics of hard parton-parton scattering through the exchange of a color singlet two-gluon ladder as described by the BFKL equation, resulting in a rapidity gap between two high transverse momentum jets. Implementing this in a complete Monte Carlo event simulation that also accounts for additional QCD processes at softer scales provides dynamical modeling of gap survival probabilities, which makes possible a detailed comparison with data on such jet-gap-jet events. New data from CMS at the LHC extend the dynamic range of the previous Tevatron data, and can be reproduced reasonably well provided that the Soft Color Interaction model is modified based on the idea of reduced resolution power of softer gluon exchanges. This indicates the need for further theoretical developments in connection with other color exchange processes related to rapidity gaps in the hadronic final state.

    hep-ph19 citations
13. 13*

    The Neutrino Option

    llaria Brivio🇩🇰 · Michael Trott🇩🇰

    The minimal seesaw scenario can radiatively generate the Higgs potential to induce electroweak symmetry breaking while supplying an origin of the Higgs vacuum expectation value from an underlying Majorana scale. If the Higgs potential and (derived) electroweak scale have this origin, the heavy $\mathrm{SU}(3)\times \mathrm{SU}(2)\times \mathrm{U}(1{)}_{\mathrm{Y}}$ singlet states are expected to reside at $m_N\sim 10-500\mathrm{PeV}$ for couplings $|\omega |\sim 10^{-4.5}-10^{-6}$ between the Majorana sector and the Standard Model. In this framework, the challenge of the electroweak scale hierarchy problem is replaced with a need to generate or accommodate PeV Majorana mass scales in ultraviolet models; the usual hierarchy problem is absent as the electroweak scale is not a fundamental scale.

    hep-phPRL(2017)·53 citations
14. 14*

    Naturally realized two dark Z's near the electroweak scale

    Jihn E. Kim🇰🇷

    Chiral representations are the key in obtaining light fermions from some ultra-violet completed theories. The well-known chiral example is one family set of fifteen chiral fields in the standard model. We find a new chiral theory SU(2)${}_{\mathrm{dark}}\times$U(1)${}_Q$ with sixteen chiral fields, which does not have any gauge and gravitational anomalies. The group SU(2)${}_{\mathrm{dark}}\times$U(1)${}_Q$ may belong to the dark sector, and we present a derivation of the spectrum from the E${}_8\times$E${}_8^{\prime }$ hetrotic string. Necessarily, there appear two degrees at low energy: two dark Z's, or a dark Z plus a dark-photon. Being chiral, there is a chance to probe this theory at TeV accelerators. Since the model belongs to the dark sector, the way to probe it is through the kinetic mixing.

    hep-phhep-thPRD(2017)·11 citations
15. 15*

    Polarization of a probe laser beam due to nonlinear QED effects

    Soroush Shakeri🇮🇷 · Seyed Zafarollah Kalantari🇮🇷 · She-Sheng Xue🇮🇹

    Nonlinear QED interactions induce different polarization properties on a given probe beam. We consider the polarization effects caused by the photon-photon interaction in laser experiments, when a laser beam propagates through a constant magnetic field or collides with another laser beam. We solve the quantum Boltzmann equation within the framework of the Euler-Heisenberg Lagrangian for both time-dependent and constant background field to explore the time evolution of the Stokes parameters Q, U, and V describing polarization. Assuming an initially linearly polarized probe laser beam, we also calculate the induced ellipticity and rotation of the polarization plane.

    hep-phhep-thphysics.atom-phPRA(2017)·17 citations
16. 16*

    Hilbert Series and Operator Basis for NRQED and NRQCD/HQET

    Andrew Kobach🇺🇸 · Sridip Pal🇺🇸

    We use a Hilbert series to construct an operator basis in the $1/m$ expansion of a theory with a nonrelativistic heavy fermion in an electromagnetic (NRQED) or color gauge field (NRQCD/HQET). We present a list of effective operators with mass dimension $d\le 8$. Comparing to the current literature, our results for NRQED agree for $d\le 8$, but there are some discrepancies in NRQCD/HQET at $d=7$ and 8.

    hep-phPLB(2017)·55 citations
17. 17*

    Onset of hydrodynamics for a quark-gluon plasma from the evolution of moments of distribution functions

    Jean-Paul Blaizot🇫🇷 · Li Yan🇨🇦

    The pre-equilibrium evolution of a quark-gluon plasma produced in a heavy-ion collision is studied in the framework of kinetic theory. We discuss the approach to local thermal equilibrium, and the onset of hydrodynamics, in terms of a particular set of moments of the distribution function. These moments quantify the momentum anisotropies to a finer degree than the commonly used ratio of longitudinal to transverse pressures. They are found to be in direct correspondence with viscous corrections of hydrodynamics, and provide therefore an alternative measure of these corrections in terms of the distortion of the momentum distribution. As an application, we study the evolution of these moments by solving the Boltzmann equation for a boost invariant expanding system, first analytically in the relaxation time approximation, and then numerically for a quark-gluon plasma within the small angle approximation to the collision kernel.

    ↳ nucl-thhep-phnucl-exJHEP(2017)·55 citations
18. 18*

    Charm semileptonic decays at LHCb

    Adam C. S. Davis (for the LHCb Collaboration)🇨🇳

    In these proceedings, we explore the possible reach of the LHCb dataset in the area of charm semileptonic decays. Specifically, we give prospects for the measurement of $|V_{cs}|/|V_{cd}|$ using $\mathcal{B}(D^0\to K^{-}{\mu }^{+}{\nu }_{\mu })/\mathcal{B}(D^0\to {\pi }^{-}{\mu }^{+}{\nu }_{\mu })$ with Run I data. Preliminary projections show that the LHCb Run I dataset would give a relative statistical uncertainty of $\sim 0.2\%$ on this ratio. We also motivate the search for lepton non-universality in the charm sector.

    ↳ hep-exhep-phPoS(2017)·3 citations
19. 19*

    Structure of the Roper Resonance from Lattice QCD Constraints

    Jia-jun Wu🇦🇺 · Derek B. Leinweber🇦🇺 · Zhan-wei Liu🇨🇳 · Anthony W. Thomas🇦🇺

    Two different descriptions of the existing pion-nucleon scattering data in the region of the Roper resonance are constructed. Both descriptions fit the experimental data very well. In one scenario the resonance is the result of strong rescattering between coupled meson-baryon channels, while in the other scenario, the resonance has a large bare-baryon (or quark-model like) component. The predictions of these two scenarios are compared with the latest lattice QCD simulation results in this channel. Consideration of the finite volume spectra, the manner in which the states are excited from the vacuum in lattice QCD and the composition of the states in Hamiltonian effective field theory enable a discrimination of these two different descriptions. We find the second scenario is not consistent with lattice QCD results whereas the first agrees with the lattice QCD constraints. In this scenario, the mass of the quark-model like state is approximately 2 GeV and in the finite volume of the lattice is dressed to place the first radial excitation of the nucleon at 1.9 GeV. Within this description, the infinite-volume Roper resonance is best described as a resonance generated dynamically through strongly coupled meson-baryon channels.

    ↳ nucl-thhep-lathep-phPRD(2018)·75 citations
20. 20*

    Cosmological Constraints on Interacting Light Particles

    Christopher Brust🇨🇦 · Yanou Cui🇺🇸 · Kris Sigurdson🇺🇸

    Cosmological observations are becoming increasingly sensitive to the effects of light particles in the form of dark radiation (DR) at the time of recombination. The conventional observable of effective neutrino number, $N_{\mathrm{eff}}$, is insufficient for probing generic, interacting models of DR. In this work, we perform likelihood analyses which allow both free-streaming effective neutrinos (parametrized by $N_{\mathrm{eff}}$) and interacting effective neutrinos (parametrized by $N_{\mathrm{fld}}$). We motivate an alternative parametrization of DR in terms of $N_{\mathrm{tot}}$ (total effective number of neutrinos) and $f_{\mathrm{fs}}$ (the fraction of effective neutrinos which are free-streaming), which is less degenerate than using $N_{\mathrm{eff}}$ and $N_{\mathrm{fld}}$. Using the Planck 2015 likelihoods in conjunction with measurements of baryon acoustic oscillations (BAO), we find constraints on the total amount of beyond the Standard Model effective neutrinos (both free-streaming and interacting) of $\Delta N_{\mathrm{tot}}<0.39$ at 2$\sigma$. In addition, we consider the possibility that this scenario alleviates the tensions between early-time and late-time cosmological observations, in particular the measurements of ${\sigma }_8$ (the amplitude of matter power fluctuations at 8$h^{-1}$ Mpc), finding a mild preference for interactions among light species. We further forecast the sensitivities of a variety of future experiments, including Advanced ACTPol (a representative CMB Stage-III experiment), CMB Stage-IV, and the Euclid satellite. This study is relevant for probing non-standard neutrino physics as well as a wide variety of new particle physics models beyond the Standard Model that involve dark radiation.

    ↳ astro-ph.COhep-phJCAP(2017)·89 citations
21. 21*

    How Does the Quark-Gluon Plasma Know the Collision Energy?

    Brett McInnes🇸🇬

    Heavy ion collisions at the LHC facility generate a Quark-Gluon Plasma (QGP) which, for central collisions, has a higher energy density and temperature than the plasma generated in central collisions at the RHIC. But sufficiently peripheral LHC collisions give rise to plasmas which have the \emph{same} energy density and temperature as the "central" RHIC plasmas. One might assume that the two versions of the QGP would have very similar properties (for example, with regard to jet quenching), but recent investigations have suggested that \emph{they do not}: the plasma "knows" that the overall collision energy is different in the two cases. We argue, using a gauge-gravity analysis, that the strong magnetic fields arising in one case (peripheral collisions), but not the other, may be relevant here. If the residual magnetic field in peripheral LHC plasmas is of the order of at least $eB\approx 5m_{\pi }^2$, then the model predicts modifications of the relevant quenching parameter which approach those recently reported.

    ↳ hep-thhep-phNPB(2018)·2 citations
22. 22*

    Origin of the high energy neutrino flux at IceCube

    J.M. Carceller🇪🇸 · J.I. Illana🇪🇸 · M. Masip🇪🇸 · D. Meloni🇮🇹

    We discuss the spectrum of the different components in the astrophysical neutrino flux reaching the Earth and the possible contribution of each component to the high-energy IceCube data. We show that the diffuse flux from cosmic ray interactions with gas in our galaxy implies just 2 events among the 54 event sample. We argue that the neutrino flux from cosmic ray interactions in the intergalactic (intracluster) space depends critically on the transport parameter $\delta$ describing the energy dependence in the diffusion coefficient of galactic cosmic rays. Our analysis motivates a E^{-2.1} neutrino spectrum with a drop at PeV energies that fits well the data, including the non-observation of the Glashow resonance at 6.3 PeV. We also show that a cosmic ray flux described by an unbroken power law may produce a neutrino flux with interesting spectral features (bumps and breaks) related to changes in the cosmic ray composition.

    ↳ astro-ph.HEhep-phApJ(2018)·4 citations
23. 23*

    Collective flow in 2.76 A TeV and 5.02 A TeV Pb+Pb collisions

    Wenbin Zhao🇨🇳 · Hao-jie Xu🇨🇳 · Huichao Song (Peking U.)🇨🇳

    In this paper, we study and predict flow observables in 2.76 A TeV and 5.02 A TeV Pb +Pb collisions, using the iEBE-VISHNU hybrid model with TRENto and AMPT initial conditions and with different forms of the QGP transport coefficients. With properly chosen and tuned parameter sets, our model calculations can nicely describe various flow observables in 2.76 A TeV Pb +Pb collisions, as well as the measured flow harmonics of all charged hadrons in 5.02 A TeV Pb +Pb collisions. We also predict other flow observables, including $v_n(p_T)$ of identified particles, event-by-event $v_n$ distributions, event-plane correlations, (Normalized) Symmetric Cumulants, non-linear response coefficients and $p_T$-dependent factorization ratios, in 5.02 A TeV Pb+Pb collisions. We find many of these observables remain approximately the same values as the ones in 2.76 A TeV Pb+Pb collisions. Our theoretical studies and predictions could shed light to the experimental investigations in the near future.

    ↳ nucl-thhep-phnucl-exEPJC(2017)·126 citations
24. 24*

    Localization of Gravitino Field on $f(R)$ Thick Branes

    Xiang-Nan Zhou🇨🇳 · Yun-Zhi Du🇨🇳 · Hao Yu🇨🇳 · Yu-Xiao Liu🇨🇳

    In this paper, we consider the localization of a five-dimensional gravitino field on $f(R)$-thick branes. We obtain the coupled chiral equations of the Kaluza-Klein (KK) modes of gravitinos with the gauge condition ${\Psi }_z=0$. The chiral equations of a gravitino's KK modes are found to be almost identical to those of the Dirac fermion. However, their chiralities are exactly opposite. The chiral KK modes of gravitinos could be localized in some types of $f(R)$-thick branes on introducing a coupling term. We investigate the localization of a gravitino on three types of $f(R)$-thick branes through a Yukawa-like coupling term with background scalar fields. It has been shown that all the KK modes of gravitinos cannot be localized in the pure geometric $f(R)$-thick branes by adding a five-dimensional gravitino mass term. However, for the $f(R)$-thick branes generated by one or two background scalar fields, only the left- or right-handed zero mode could be localized in the branes, and the massive KK resonant modes are the same for both left- and right-handed gravitinos despite their opposing chiralities. All these results are consistent with those of the five-dimensional Dirac fermion except their chiralities, which may be an important sign to distinguish the gravitino field and the Dirac fermion field.

    ↳ hep-thgr-qchep-phSCPMA(2018)·23 citations
25. 25*

    Anisotropic fluid dynamics for Gubser flow

    M. Martinez🇺🇸 · M. McNelis🇺🇸 · U. Heinz🇺🇸

    Exploring a variety of closing schemes to the infinite hierarchy of momentum moments of the exactly solvable Boltzmann equation for systems undergoing Gubser flow, we study the precision with which the resulting hydrodynamic equations reproduce the exact evolution of hydrodynamic moments of the distribution function. We find that anisotropic hydrodynamics, obtained by ex- panding the distribution function around a dynamically evolving locally anisotropic background whose evolution is matched to exactly reproduce the macroscopic pressure anisotropy caused by the different longitudinal and transverse expansion rates in Gubser flow, provides the most accurate macroscopic description of the microscopic kinetic evolution. This confirms a similar earlier finding for Bjorken flow [Molnár, Niemi and Rischke, Phys. Rev. D 94, 125003 (2016)]. We explain the physics behind this optimal matching procedure and show that one can efficiently correct for a non- optimized matching choice by adding a residual shear stress to the energy-momentum tensor whose evolution is again determined by the Boltzmann equation. Additional insights to guide the optimal choice of a macroscopic anisotropic hydrodynamic framework for strongly-coupled systems that do not admit a microscopic kinetic description are reported.

    ↳ nucl-thhep-phPRC(2017)·48 citations
26. 26*

    Revisiting the decoupling effects in the running of the Cosmological Constant

    Oleg Antipin🇭🇷 · Blazenka Melic🇭🇷

    We revisit the decoupling effects associated with heavy particles in the renormalization group running of the vacuum energy in a mass-dependent renormalization scheme. We find the running of the vacuum energy stemming from the Higgs condensate in the entire energy range and show that it behaves as expected from the simple dimensional arguments meaning that it exhibits the quadratic sensitivity to the mass of the heavy particles in the infrared regime. The consequence of such a running to the fine-tuning problem with the measured value of the Cosmological Constant is analyzed and the constraint on the mass spectrum of a given model is derived. We show that in the Standard Model (SM) this fine-tuning constraint is not satisfied while in the massless theories this constraint formally coincides with the well known Veltman condition. We also provide a remarkably simple extension of the SM where saturation of this constraint enables us to predict the radiative Higgs mass correctly. Generalization to constant curvature spaces is also given.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2017)·13 citations
27. 27*

    Neutrino Intensity Interferometry: Measuring Proto-neutron Star Radii During Core-Collapse Supernovae

    Warren P. Wright🇺🇸 · James P. Kneller🇺🇸

    Intensity interferometry is a technique that has been used to measure the size of sources ranging from the quark-gluon plasma formed in heavy ion collisions to the radii of stars. We investigate using the same technique to measure proto-neutron star (PNS) radii with the neutrino signal received from a core-collapse supernovae. Using a full wave-packet analysis, including the neutrino mass for the first time, we derive criteria where the effect can be expected to provide the desired signal, and find that neutrinos from the next Galactic supernova should contain extractable PNS radius information.

    ↳ astro-ph.HEhep-phPRL(2017)·9 citations
28. 28*

    Linking High-Energy Cosmic Particles by Black-Hole Jets Embedded in Large-Scale Structures

    Ke Fang (U. Maryland)🇺🇸 · Kohta Murase (PSU)🇺🇸

    The origin of ultrahigh-energy cosmic rays (UHECRs) is a half-century old enigma (Linsley 1963). The mystery has been deepened by an intriguing coincidence: over ten orders of magnitude in energy, the energy generation rates of UHECRs, PeV neutrinos, and isotropic sub-TeV gamma rays are comparable, which hints at a grand-unified picture (Murase and Waxman 2016). Here we report that powerful black hole jets in aggregates of galaxies can supply the common origin of all of these phenomena. Once accelerated by a jet, low-energy cosmic rays confined in the radio lobe are adiabatically cooled; higher-energy cosmic rays leaving the source interact with the magnetized cluster environment and produce neutrinos and gamma rays; the highest-energy particles escape from the host cluster and contribute to the observed cosmic rays above 100 PeV. The model is consistent with the spectrum, composition, and isotropy of the observed UHECRs, and also explains the IceCube neutrinos and the non-blazar component of the Fermi gamma-ray background, assuming a reasonable energy output from black hole jets in clusters.

    ↳ astro-ph.HEastro-ph.COhep-phNat.Phys.(2018)·198 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.