Fri·Feb 5, 2016Friday·February 5, 2016

1. 01*

   On the maximal diphoton width

   Alberto Salvio🇨🇭 · Florian Staub🇨🇭 · Alessandro Strumia🇨🇭 · Alfredo Urbano🇨🇭

   Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal width into $\gamma \gamma$ that a neutral scalar can acquire through a loop of charged fermions or scalars as function of the maximal scale at which the theory holds, taking into account vacuum (meta)stability bounds. We show how an extra gauge symmetry can qualitatively weaken such bounds, and explore collider probes and connections with Dark Matter.

   hep-phJHEP(2016)·47 citations
2. 02*

   Dark Sunshine: Detecting Dark Matter through Dark Photons from the Sun

   Jonathan L. Feng🇺🇸 · Jordan Smolinsky🇺🇸 · Philip Tanedo🇺🇸

   Dark matter may interact with the Standard Model through the kinetic mixing of dark photons, $A^{\prime }$, with Standard Model photons. Such dark matter will accumulate in the Sun and annihilate into dark photons. The dark photons may then leave the Sun and decay into pairs of charged Standard Model particles that can be detected by the Alpha Magnetic Spectrometer. The directionality of this "dark sunshine" is distinct from all astrophysical backgrounds, providing an opportunity for unambiguous dark matter discovery by AMS. We perform a complete analysis of this scenario including Sommerfeld enhancements of dark matter annihilation and the effect of the Sun's magnetic field on the signal, and we define a set of cuts to optimize the signal probability. With the three years of data already collected, AMS may discover dark matter with mass 1 TeV $\lesssim m_X\lesssim$ 10 TeV, dark photon masses $m_{A^{\prime }}\sim \mathcal{O}(100)$ MeV, and kinetic mixing parameters $10^{-10}\lesssim \epsilon \lesssim 10^{-8}$. The proposed search extends beyond existing beam dump and supernova bounds, and it is complementary to direct detection, probing the same region of parameter space for elastic dark matter, but potentially far more in the case of inelastic dark matter.

   hep-phastro-ph.COastro-ph.HEhep-exPRD(2016)·113 citations
3. 03*

   Pseudoscalar susceptibilities and quark condensates: chiral restoration and lattice screening masses

   A. Gomez Nicola🇪🇸 · J. Ruiz de Elvira🇩🇪

   We derive the formal Ward identities relating pseudoscalar susceptibilities and quark condensates in three-flavor QCD, including consistently the $\eta$-${\eta }^{\prime }$ sector and the $U_A(1)$ anomaly. These identities are verified in the low-energy realization provided by ChPT, both in the standard $SU(3)$ framework for the octet case and combining the use of the $U(3)$ framework and the large-$N_c$ expansion of QCD to account properly for the nonet sector and anomalous contributions. The analysis is performed including finite temperature corrections as well as the calculation of $U(3)$ quark condensates and all pseudoscalar susceptibilities, which together with the full set of Ward identities, are new results of this work. Finally, the Ward identities are used to derive scaling relations for pseudoscalar masses, which explain the behavior with temperature of lattice screening masses near chiral symmetry restoration.

   hep-phhep-latJHEP(2016)·38 citations
4. 04*

   Differential equations and dispersion relations for Feynman amplitudes. The two-loop massive sunrise and the kite integral

   Ettore Remiddi🇮🇹 · Lorenzo Tancredi🇩🇪

   It is shown that the study of the imaginary part and of the corresponding dispersion relations of Feynman graph amplitudes within the differential equations method can provide a powerful tool for the solution of the equations, especially in the massive case. The main features of the approach are illustrated by discussing the simple cases of the 1-loop self-mass and of a particular vertex amplitude, and then used for the evaluation of the two-loop massive sunrise and the QED kite graph (the problem studied by Sabry in 1962), up to first order in the (d-4) expansion.

   hep-phNPB(2016)·176 citations
5. 05*

   Reactor antineutrino fluxes - status and challenges

   Patrick Huber🇺🇸

   In this contribution we describe the current understanding of reactor antineutrino fluxes and point out some recent developments. This is not intended to be a complete review of this vast topic but merely a selection of observations and remarks, which despite their incompleteness, will highlight the status and the challenges of this field.

   hep-phnucl-thphysics.ins-detNPB(2016)·51 citations
6. 06*

   A Hydrodynamic Approach to the Study of Anisotropic Instabilities in Dissipative Relativistic Plasmas

   Esteban Calzetta🇦🇷 · Alejandra Kandus🇧🇷

   We develop a purely hydrodynamic formalism to describe collisional, anisotropic instabilities in a relativistic plasma, that are usually described with kinetic theory tools. Our main motivation is the fact that coarse-grained models of high particle number systems give more clear and comprehensive physical descriptions of those systems than purely kinetic approaches, and can be more easily tested experimentally as well as numerically. In particular, we aim at developing a theory that describes both a background non-equilibrium fluid configurations and its perturbations, to be able to account for the backreaction of the latter on the former. Our system of equations includes the usual conservation laws for the energy-momentum tensor and for the electric current, and the equations for two new tensors that encode the information about dissipation. To make contact with kinetic theory, we write the different tensors as the moments of a non-equilibrium one-particle distribution function (1pdf) which, for illustrative purposes, we take in the form of a Grad-like ansatz. Although this choice limits the applicability of the formalism to states not far from equilibrium, it retains the main features of the underlying kinetic theory. We assume the validity of the Vlasov-Boltzmann equation, with a collision integral given by the Anderson-Witting prescription, which is more suitable for highly relativistic systems than Marle's (or Bhatnagar, Gross and Krook) form, and derive the conservation laws by taking its corresponding moments. We apply our developments to study the emergence of instabilities in an anisotropic, but axially symmetric background. For small departures of isotropy we find the dispersion relation for normal modes, which admit unstable solutions for a wide range of values of the parameter space.

   hep-phnucl-thphysics.flu-dynInt.J.Mod.Phys.A(2016)·8 citations
7. 07*

   Speed of Sound in Hadronic matter using Non-extensive Tsallis Statistics

   Arvind Khuntia🇮🇳 · Pragati Sahoo🇮🇳 · Prakhar Garg🇮🇳 · Raghunath Sahoo🇮🇳 · Jean Cleymans🇿🇦

   The speed of sound ($c_s$) is studied to understand the hydrodynamical evolution of the matter created in heavy-ion collisions. The quark-gluon plasma (QGP) formed in heavy-ion collisions evolves from an initial QGP to the hadronic phase via a possible mixed phase. Due to the system expansion in a first order phase transition scenario, the speed of sound reduces to zero as the specific heat diverges. We study the speed of sound for systems, which deviate from a thermalized Boltzmann distribution using non-extensive Tsallis statistics. In the present work, we calculate the speed of sound as a function of temperature for different $q$-values for a hadron resonance gas. We observe a similar mass cut-off behaviour in non-extensive case for $c_s^2$ by including heavier particles, as is observed in the case of a hadron resonance gas following equilibrium statistics. Also, we explicitly present that the temperature where the mass cut-off starts, varies with the $q$-parameter which hints at a relation between the degree of non-equilibrium and the limiting temperature of the system. It is shown that for values of $q$ above approximately 1.13 all criticality disappear in the speed of sound, i.e. the decrease in the value of the speed of sound, observed at lower values of $q$, disappears completely.

   hep-phnucl-exnucl-thEPJA(2016)·28 citations
8. 08*

   Thermal Charm and Charmonium Production in Quark Gluon Plasma

   Kai Zhou🇨🇳 · Zhengyu Chen🇨🇳 · Carsten Greiner🇩🇪 · Pengfei Zhuang🇨🇳

   We study the effect of thermal charm production on charmonium regeneration in high energy nuclear collisions. By solving the kinetic equations for charm quark and charmonium distributions in Pb+Pb collisions, we calculate the global and differential nuclear modification factors $R_{AA}(N_{part})$ and $RAA(p_t)$ for $J/\Psi$s. Due to the thermal charm production in hot medium, the charmonium production source changes from the initially created charm quarks at SPS, RHIC and LHC to the thermally produced charm quarks at Future Circular Collider (FCC), and the $J/\Psi$ suppression ($R_{AA}<1$) observed so far will be replaced by a strong enhancement ($R_{AA}>1$) at FCC at low transverse momentum.

   hep-phnucl-exnucl-thPLB(2016)·33 citations
9. 09*

   Coupling between Majorana fermions and Nambu-Goldstone bosons inside a non-Abelian vortex in dense QCD

   Chandrasekhar Chatterjee🇯🇵 · Mattia Cipriani🇮🇹 · Muneto Nitta🇯🇵

   Quark matter at high density may exhibit color superconductivity. As magnetic flux tubes in metallic superconductors, color magnetic flux tubes as non-Abelian vortices appear in the color-flavor locked phase of high density QCD. $\mathbb{C}{P}^2$ Nambu-Goldstone bosons and Majorana fermions belonging to the triplet representation are known to be localized around a non-Abelian vortex. In this paper, we determine the coupling of these bosonic and fermionic modes by using the nonlinear realization method.

   hep-phcond-mat.supr-conhep-thPRD(2016)·13 citations
10. 10*

    Contact Interactions in Higgs-Vector Boson Associated Production at the ILC

    Jonathan Cohen🇮🇱 · Shaouly Bar-Shalom🇮🇱 · Gad Eilam🇮🇱

    We explore new physics (NP) effects in Higgs-Vector boson associated production at a future International Linear Collider (ILC) via e+e- -> Zh,Zhh, using effective field theory (EFT) techniques. In particular, we focus on a certain class of dimension 6 operators, which are generated by tree-level exchanges of a new heavy vector field in the underlying theory. These operators induce new contact terms of the form \psi\psi\phi D\phi, involving the Standard Model (SM) fermions (\psi), gauge-bosons (D is the covariant derivative) and the SM Higgs field (\phi). We investigate the high-energy behaviour of these new effective interactions in e+e- -> Zh,Zhh, imposing bounds from electroweak precision measurements, and show that the ILC is an excellent testing ground for probing this type of NP via e+e- -> Zh,Zhh. We also address the validity of the EFT expansion and we study the correlation between the hZ and hhZ signals, which can be utilized in future searches for NP in these channels.

    hep-phhep-exPRD(2016)·19 citations
11. 11*

    Radiative natural SUSY spectrum from deflected AMSB scenario with messenger-matter interactions

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

    A radiative natural SUSY spectrum are proposed in the deflected anomaly mediation scenario with general messenger-matter interactions. Due to the contributions from the new interactions, positive slepton masses as well as a large |A_t| term can naturally be obtained with either sign of deflection parameter and few messenger species (thus avoid the possible Landau pole problem). In this scenario, in contrast to the ordinary (radiative) natural SUSY scenario with under-abundance of dark matter (DM), the DM can be the mixed bino-higgsino and have the right relic density. The 125 GeV Higgs mass can also be easily obtained in our scenario. The majority of low EW fine tuning points can be covered by the XENON-1T direct detection experiments.

    hep-phJHEP(2016)·22 citations
12. 12*

    The Price of an Electroweak Monopole

    John Ellis🇬🇧 · Nick E. Mavromatos🇬🇧 · Tevong You🇬🇧

    In a recent paper, Cho, Kim and Yoon (CKY) have proposed a version of the SU(2) $\times$ U(1) Standard Model with finite-energy monopole and dyon solutions. The CKY model postulates that the effective U(1) gauge coupling $\to \infty$ very rapidly as the Englert-Brout-Higgs vacuum expectation value $\to 0$, but in a way that is incompatible with LHC measurements of the Higgs boson $H\to \gamma \gamma$ decay rate. We construct generalizations of the CKY model that are compatible with the $H\to \gamma \gamma$ constraint, and calculate the corresponding values of the monopole and dyon masses. We find that the monopole mass could be $<5.5$ TeV, so that it could be pair-produced at the LHC and accessible to the MoEDAL experiment.

    hep-phhep-exhep-thPLB(2016)·104 citations
13. 13*

    Twist expansion of forward Drell-Yan process

    Tomasz Stebel🇵🇱 · Leszek Motyka🇵🇱 · Mariusz Sadzikowski🇵🇱

    We present a twist expansion of differential cross-sections of the forward Drell-Yan process at the high energies. The expansion of all invariant form-factors is performed assuming GBW saturation model and the saturation scale plays the role of the hadronic scale of OPE. Some expilicit predictions for LHC experiments are given. It is shown also how the Lam-Tung relation is broken at twist 4 what provides a sensitive probe for searching of higher twists.

    hep-phActa Phys.Polon.Supp.(2015)·1 citation
14. 14*

    High-energy resummation effects in the production of Mueller-Navelet dijet at the LHC

    B. Ducloué🇫🇮 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷

    We study the production of two forward jets with a large interval of rapidity at hadron colliders, which was proposed by Mueller and Navelet as a possible test of the high energy dynamics of QCD, within a complete next-to-leading logarithm framework. We show that using the Brodsky-Lepage-Mackenzie procedure to fix the renormalization scale leads to a very good description of the recent CMS data at the LHC for the azimuthal correlations of the jets. We show that the inclusion of next-to-leading order corrections to the jet vertex significantly reduces the importance of energy-momentum non-conservation which is inherent to the BFKL approach, for an asymmetric jet configuration. Finally, we argue that the double parton scattering contribution is negligible in the kinematics of actual CMS measurements.

    hep-phhep-exEPJ Web Conf.(2016)·0 citations
15. 15*

    Revealing transversity GPDs through the photoproduction of a photon and a $\rho$ meson

    R. Boussarie🇫🇷 · B. Pire🇫🇷 · L. Szymanowski🇵🇱 · S. Wallon🇫🇷

    Photoproduction of a pair of particles with large invariant mass is a natural extension of collinear QCD factorization theorems which have been much studied for deeply virtual Compton scattering and deeply virtual meson production. We discuss the production of a photon and a meson, where the wide angle Compton scattering on a meson subprocess factorizes from generalized parton distribution. We calculate at dominant twist and leading order in ${\alpha }_s$, the production cross-section of a transversely polarized $\rho$ meson which is sensitive to chiral-odd GPDs, and show that it may be measurable in near future JLab experiments.

    hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2016)·8 citations
16. 16*

    Roberge-Weiss endpoint at the physical point of $N_f=2+1$ QCD

    Claudio Bonati🇮🇹 · Massimo D'Elia🇮🇹 · Marco Mariti🇮🇹 · Michele Mesiti🇮🇹 · Francesco Negro🇮🇹 · Francesco Sanfilippo🇬🇧

    We study the phase diagram of $N_f=2+1$ QCD in the $T-{\mu }_B$ plane and investigate the critical point corresponding to the onset of the Roberge-Weiss transition, which is found for imaginary values of ${\mu }_B$. We make use of stout improved staggered fermions and of the tree level Symanzik gauge action, and explore four different sets of lattice spacings, corresponding to $N_t=4,6,8,10$, and different spatial sizes, in order to assess the universality class of the critical point. The continuum extrapolated value of the endpoint temperature is found to be $T_{\mathrm{RW}}=208(5)$ MeV, i.e. $T_{\mathrm{RW}}/T_c\sim 1.34(7)$, where $T_c$ is the chiral pseudocritical temperature at zero chemical potential, while our finite size scaling analysis, performed on $N_t=4$ and $N_t=6$ lattices, provides evidence for a critical point in the $3d$ Ising universality class.

    ↳ hep-lathep-phhep-thPRD(2016)·66 citations
17. 17*

    Electromagnetic radiation as a probe of the initial state and of viscous dynamics in relativistic nuclear collisions

    Gojko Vujanovic🇺🇸 · Jean-François Paquet🇨🇦 · Gabriel S. Denicol🇨🇦 · Matthew Luzum🇪🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    The penetrating nature of electromagnetic signals makes them suitable probes to explore the properties of the strongly-interacting medium created in relativistic nuclear collisions. We examine the effects of the initial conditions and shear relaxation time on the spectra and flow coefficients of electromagnetic probes, using an event-by-event 3+1D viscous hydrodynamic simulation (MUSIC).

    ↳ nucl-thhep-phnucl-exPRC(2016)·47 citations
18. 18*

    Coherent photoproduction of vector mesons in heavy ion ultraperipheral collisions: Update for run 2 at the CERN Large Hadron Collider

    V. Guzey🇷🇺 · E. Kryshen🇷🇺 · M. Zhalov (PNPI, Gatchina)🇷🇺

    We make predictions for the cross sections of coherent photoproduction of $\rho$, $\varphi$, $J/\psi$, $\psi (2S)$, and ${\rm Y}(1S)$ mesons in Pb-Pb ultraperipheral collisions (UPCs) at $\sqrt{s_{NN}}=5.02$ TeV in the kinematics of run 2 at the Large Hadron Collider extending the approaches successfully describing the available Pb-Pb UPC data at $\sqrt{s_{NN}}=2.76$ TeV. Our results illustrate the important roles of hadronic fluctuations of the photon and inelastic nuclear shadowing in photoproduction of light vector mesons on nuclei and the large leading twist nuclear gluon shadowing in photoproduction of quarkonia on nuclei. We show that the ratio of $\psi (2S)$ and $J/\psi$ photoproduction cross sections in Pb-Pb UPCs is largely determined by the ratio of these cross sections on the proton. We also argue that UPCs with electromagnetic excitations of the colliding ions followed by the forward neutron emission allows one to significantly increase the range of photon energies accessed in vector meson photoproduction on nuclei.

    ↳ nucl-thhep-phnucl-exPRC(2016)·108 citations
19. 19*

    Valence-quark distribution functions in the kaon and pion

    Chen Chen🇨🇳 · Lei Chang🇨🇳 · Craig D. Roberts🇺🇸 · Shaolong Wan🇨🇳 · Hong-Shi Zong🇨🇳

    We describe expressions for pion and kaon dressed-quark distribution functions that incorporate contributions from gluons which bind quarks into these mesons and hence overcome a flaw of the commonly used handbag approximation. The distributions therewith obtained are purely valence in character, ensuring that dressed-quarks carry all a meson's momentum at a characteristic hadronic scale and vanishing as $(1-x{)}^2$ when Bjorken-$x\to 1$. Comparing such distributions within the pion and kaon, it is apparent that the size of SU(3)-flavour symmetry breaking in meson parton distribution functions is modulated by the flavour dependence of dynamical chiral symmetry breaking. Corrections to these leading-order formulae may be divided into two classes, responsible for shifting dressed-quark momentum into glue and sea-quarks. Working with available empirical information, we build an algebraic framework that is capable of expressing the principal impact of both classes of corrections. This enables a realistic comparison with experiment which allows us to identify and highlight basic features of measurable pion and kaon valence-quark distributions. We find that whereas roughly two-thirds of the pion's light-front momentum is carried by valence dressed-quarks at a characteristic hadronic scale, this fraction rises to 95% in the kaon; evolving distributions with these features to a scale typical of available Drell-Yan data produces a kaon-to-pion ratio of u-quark distributions that is in agreement with the single existing data set; and predict a u-quark distribution within the pion that agrees with a modern reappraisal of $\pi N$ Drell-Yan data. Precise new data are essential in order to validate this reappraisal and because a single modest-quality measurement of the kaon-to-pion ratio cannot be considered definitive.

    ↳ nucl-thhep-exhep-lathep-ph+1PRD(2016)·124 citations
20. 20*

    Energetic emissions from deconfinement in compact stars and their relation to the critical end point in the QCD phase diagram

    D. E. Alvarez-Castillo🇷🇺

    In this work we study the case of deconfinement in compact star interiors in the presence of a strong first order phase transition associated to a critical end point in the QCD phase diagram. Neutron stars fulfilling these conditions show a third branch in the mass-radius diagram with the first and second branches being the white dwarfs and neutron stars configurations. The transition to the third branch can be reached by a pure hadronic neutron star through an induced collapse releasing energy that corresponds to a mass-energy difference between the second and third branch configurations. Physical outcomes of this phenomenon that can potentially explain the already detected astrophysical signals are discussed. In particular we present energy estimations for the case of a fast radio burst, seen as a double-peak structure in the object's light curve.

    ↳ astro-ph.HEhep-phnucl-thPublishing house Sneg, Pyatigorsk (2016) …·0 citations
21. 21*

    Beam energy dependence of Hanbury-Brown-Twiss radii from a blast-wave model

    S. Zhang🇨🇳 · Y. G. Ma🇨🇳 · J. H. Chen🇨🇳 · C. Zhong🇨🇳

    The beam energy dependence of correlation lengths (the Hanbury-Brown-Twiss radii) is calculated by using a blast-wave model and the results are comparable with those from RHIC-STAR beam energy scan data as well as the LHC-ALICE measurements. A set of parameter for the blast-wave model as a function of beam energy under study are obtained by fit to the HBT radii at each energy point. The transverse momentum dependence of HBT radii is presented with the extracted parameters for Au + Au collision at $\sqrt{s_{NN}}=$ 200 GeV and for Pb+Pb collisions at 2.76 TeV. From our study one can learn that particle emission duration can not be ignored while calculating the HBT radii with the same parameters. And tuning kinetic freeze-out temperature in a range will result in system lifetime changing in the reverse direction as it is found in RHIC-STAR experiment measurements.

    ↳ nucl-thhep-phnucl-exAdv.High Energy Phys.(2016)·17 citations
22. 22*

    Testing Einstein's Weak Equivalence Principle With Gravitational Waves

    Xue-Feng Wu · He Gao · Jun-Jie Wei · Xi-Long Fan · Peter Mészáros · Bing Zhang · Zi-Gao Dai · Shuang-Nan Zhang · Zong-Hong Zhu

    A conservative constraint on the Einstein Weak Equivalence Principle (WEP) can be obtained under the assumption that the observed time delay between correlated particles from astronomical sources is dominated by the gravitational fields through which they move. Current limits on the WEP are mainly based on the observed time delays of photons with different energies. It is highly desirable to develop more accurate tests that include the gravitational wave (GW) sector. The detection by the advanced LIGO/VIRGO systems of gravitational waves will provide attractive candidates for constraining the WEP, extending the tests to gravitational interactions, with potentially higher accuracy. Considering the capabilities of the advanced LIGO/VIRGO network and the source direction uncertainty, we show that the joint detection of GWs and electromagnetic signals could probe the WEP to an accuracy down to $10^{-10}$, which is one order of magnitude tighter than previous limits, and seven orders of magnitude tighter than the multi-messenger (photons and neutrinos) results by supernova 1987A.

    ↳ astro-ph.HEgr-qchep-phPRD(2016)·61 citations
23. 23*

    Isospin properties of quark matter from a 3-flavor NJL model

    He Liu🇨🇳 · Jun Xu🇨🇳 · Lie-Wen Chen🇨🇳 · Kai-Jia Sun🇨🇳

    We have studied the properties of hot and dense quark matter based on the 3-flavor Nambu-Jona-Lasinio (NJL) model as well as its Polyakov-loop extension (pNJL) with scalar-isovector and vector-isovector couplings. Provided a considerable large isospin asymmetry or isospin chemical potential, isospin splittings of constituent mass, chiral phase transition boundary, and critical point for $u$ and $d$ quarks can be observed for positive isovector coupling constants but are suppressed for negative ones. The quark matter symmetry energy decreases with the increasing isovector coupling constant, and is mostly enhanced in the pNJL model than in the NJL model. A positive scalar-isovector coupling constant is more likely to lead to an unstable isospin asymmetric quark matter. The isovector coupling has been further found to affect particle fractions as well as the equation of state in hybrid stars. Possible effects on the isospin properties of quark matter have also been discussed if the strangeness sector is further broken among the flavor symmetry.

    ↳ nucl-thhep-phPRD(2016)·37 citations
24. 24*

    Modeling the Landau-Gauge Ghost Propagator in 2, 3 and 4 Space-Time Dimensions

    Attilio Cucchieri🇧🇷 · David Dudal🇧🇪 · Tereza Mendes🇧🇷 · Nele Vandersickel🇧🇪

    We present an analytic description of numerical results for the ghost propagator G(p^2) in minimal Landau gauge on the lattice. The data were produced in the SU(2) case using the largest lattice volumes to date, for d = 2, 3 and 4 space-time dimensions. Our proposed form for G(p^2) is derived from the one-loop relation between ghost and gluon propagators, considering a tree-level ghost-gluon vertex and our previously obtained gluon-propagator results \cite{Cucchieri:2011ig}. Although this one-loop expression is not a good description of the data, it leads to a one-parameter fit of our ghost-propagator data with a generally good value of \chi^2/dof, comparable to other fitting forms used in the literature. At the same time, we present a simple parametrization of the difference between the lattice data and the one-loop predictions.

    ↳ hep-lathep-phhep-thPRD(2016)·29 citations
25. 25*

    Constraints on the Coupling between Dark Energy and Dark Matter from CMB data

    Riccardo Murgia🇮🇹 · Stefano Gariazzo🇮🇹 · Nicolao Fornengo🇮🇹

    We investigate a phenomenological non-gravitational coupling between dark energy and dark matter, where the interaction in the dark sector is parameterized as an energy transfer either from dark matter to dark energy or the opposite. The models are constrained by a whole host of updated cosmological data: cosmic microwave background temperature anisotropies and polarization, high-redshift supernovae, baryon acoustic oscillations, redshift space distortions and gravitational lensing. Both models are found to be compatible with all cosmological observables, but in the case where dark matter decays into dark energy, the tension with the independent determinations of $H_0$ and ${\sigma }_8$, already present for standard cosmology, increases: this model in fact predicts lower $H_0$ and higher ${\sigma }_8$, mostly as a consequence of the higher amount of dark matter at early times, leading to a stronger clustering during the evolution. Instead, when dark matter is fed by dark energy, the reconstructed values of $H_0$ and ${\sigma }_8$ nicely agree with their local determinations, with a full reconciliation between high- and low-redshift observations. A non-zero coupling between dark energy and dark matter, with an energy flow from the former to the latter, appears therefore to be in better agreement with cosmological data.

    ↳ astro-ph.COhep-phJCAP(2016)·154 citations
26. 26*

    Lattice calculation of the leading strange quark-connected contribution to the muon $g-2$

    T. Blum🇺🇸 · P.A. Boyle🇬🇧 · L. Del Debbio🇬🇧 · R.J. Hudspith🇨🇦 · T. Izubuchi🇺🇸 · A. Jüttner🇬🇧 · C. Lehner🇺🇸 · R. Lewis🇨🇦 · K. Maltman🇨🇦 · M. Krstić Marinković🇬🇧 · A. Portelli🇬🇧 · M. Spraggs🇬🇧

    We present results for the leading hadronic contribution to the muon anomalous magnetic moment due to strange quark-connected vacuum polarisation effects. Simulations were performed using RBC--UKQCD's $N_f=2+1$ domain wall fermion ensembles with physical light sea quark masses at two lattice spacings. We consider a large number of analysis scenarios in order to obtain solid estimates for residual systematic effects. Our final result in the continuum limit is $a_{\mu }^{(2)\mathrm{had},s}=53.1(9)\left({}_{-3}^{+1}\right)\times 10^{-10}$.

    ↳ hep-lathep-phJHEP(2016)·46 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.