Wed·Sep 9, 2015Wednesday·September 9, 2015

1. 01*

   Towards an improved understanding of $\eta \to {\gamma }^{\ast }{\gamma }^{\ast }$

   S. Holz🇩🇪 · J. Plenter🇩🇪 · C. W. Xiao🇩🇪 · T. Dato🇩🇪 · C. Hanhart🇩🇪 · B. Kubis🇩🇪 · U.-G. Meißner🇩🇪 · A. Wirzba🇩🇪

   We argue that high-quality data on the reaction $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\eta$ will allow one to determine the doubly-virtual form factor $\eta \to {\gamma }^{\ast }{\gamma }^{\ast }$ in a model-independent way with controlled accuracy. This is an important step towards a reliable evaluation of the hadronic light-by-light scattering contribution to the anomalous magnetic moment of the muon. When analyzing the existing data for $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\eta$ for total energies squared $k^2>1{\text{GeV}}^2$, we demonstrate that the effect of the $a_2$ meson provides a natural breaking mechanism for the commonly employed factorization ansatz in the doubly-virtual form factor $F_{\eta {\gamma }^{\ast }{\gamma }^{\ast }}(q^2,k^2)$. However, better data are needed to draw firm conclusions.

   hep-phhep-exnucl-thEPJC(2021)·88 citations
2. 02*

   Fine structure of the diffraction cone: from ISR to the LHC

   D.A. Fagundes🇧🇷 · L. Jenkovszky🇺🇦 · E.Q. Miranda🇨🇺 · G. Pancheri🇮🇹 · P.V.R.G. Silva🇧🇷

   Following earlier findings, we argue that the low-$|t|$ structure in the elastic diffractive cone, recently reported by the TOTEM Collaboration at $8$ TeV, is a consequence of the threshold singularity required by $t-$channel unitarity, such as revealed earlier at the ISR. By using simple Regge-pole models, we analyze the available data on the $pp$ elastic differential cross section in a wide range of c.m. energies, namely those from ISR to LHC8, obtaining good fits of all datasets. This study hints at the fact that the non-exponential behaviour observed at LHC8 is a recurrence of the low-$|t|$ "break" phenomenon, observed in the seventies at ISR, being induced by the presence of a two-pion loop singularity in the Pomeron trajectory.

   hep-phhep-exGribov-85 Memorial Volume: Exploring Quan…·10 citations
3. 03*

   Fuzzy Jets

   Lester Mackey🇺🇸 · Benjamin Nachman🇺🇸 · Ariel Schwartzman🇺🇸 · Conrad Stansbury🇺🇸

   Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

   hep-phstat.MLJHEP(2016)·18 citations
4. 04*

   AMS-02 fits Dark Matter

   Csaba Balázs🇦🇺 · Tong Li🇦🇺

   In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified dark matter model. We include known, standard astrophysical sources and a dark matter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the dark matter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the dark matter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the dark matter hypothesis within the uncertainties, but adding a dark matter contribution improves the fit to the data. Assuming, however, that dark matter is solely responsible for this improvement of the fit, it is difficult to evade the latest CMB limits in this model.

   hep-phJHEP(2016)·4 citations
5. 05*

   Leptonic Decays of Charged Pseudoscalar Mesons - 2015

   Jonathan L. Rosner🇺🇸 · Sheldon Stone🇺🇸 · Ruth S. Van de Water🇺🇸

   We review the physics of purely leptonic decays of ${\pi }^{\pm }$, $K^{\pm }$, $D^{\pm }$, $D_s^{\pm }$, and $B^{\pm }$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for ${\pi }^{\pm }$, $K^{\pm }$, $D^{\pm }$, $D_s^{\pm }$, and $B^{\pm }$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be used to test the unitarity of the first and second rows of the CKM matrix. Conversely, taking the CKM elements predicted by unitarity, one can infer "experimental" values for $f_P$ that can be compared with theory. These provide tests of lattice-QCD methods, provided new-physics contributions to leptonic decays are negligible at the current level of precision. This review is the basis of the article in the Particle Data Group's 2016 edition, updating the versions in Refs. [1-3].

   hep-phhep-exhep-lat152 citations
6. 06*

   Phenomenological and theoretical developments in jet physics at the LHC

   Matteo Cacciari🇫🇷

   We review the history of jets in high energy physics, and describe in more detail the developments of the past ten years, discussing new algorithms for jet finding and their main characteristics, and summarising the status of perturbative calculations for jet cross sections in hadroproduction. We also describe the emergence of jet grooming and tagging techniques and their application to boosted jets analyses.

   hep-phInt.J.Mod.Phys.A(2015)·20 citations
7. 07*

   Relic Right-handed Dirac Neutrinos and Implications for Detection of Cosmic Neutrino Background

   Jue Zhang🇨🇳 · Shun Zhou🇨🇳

   It remains to be determined experimentally if massive neutrinos are Majorana or Dirac particles. In this connection, it has been recently suggested that the detection of cosmic neutrino background of left-handed neutrinos ${\nu }_{\mathrm{L}}^{}$ and right-handed antineutrinos ${\overline{\nu }}_{\mathrm{R}}^{}$ in future experiments of neutrino capture on beta-decaying nuclei (e.g., ${\nu }_e^{}+{}^3\mathrm{H}\to {}^3\mathrm{He}+e^{-}$ for the PTOLEMY experiment) is likely to distinguish between Majorana and Dirac neutrinos, since the capture rate is twice larger in the former case. In this paper, we investigate the possible impact of right-handed neutrinos on the capture rate, assuming that massive neutrinos are Dirac particles and both right-handed neutrinos ${\nu }_{\mathrm{R}}^{}$ and left-handed antineutrinos ${\overline{\nu }}_{\mathrm{L}}^{}$ can be efficiently produced in the early Universe. It turns out that the capture rate can be enhanced at most by $28\%$ due to the presence of relic ${\nu }_{\mathrm{R}}^{}$ and ${\overline{\nu }}_{\mathrm{L}}^{}$ with a total number density of $95{\mathrm{cm}}^{-3}$, which should be compared to the number density $336{\mathrm{cm}}^{-3}$ of cosmic neutrino background. The enhancement has actually been limited by the latest cosmological and astrophysical bounds on the effective number of neutrino generations $N_{\mathrm{eff}}^{}=3.14_{-0.43}^{+0.44}$ at the $95\%$ confidence level. For illustration, two possible scenarios have been proposed for thermal production of right-handed neutrinos in the early Universe.

   hep-phastro-ph.COhep-exNPB(2016)·36 citations
8. 08*

   $Gamma(H\to b\bar{b})$ to order $\alpha {\alpha }_s$

   Luminita Mihaila🇩🇪 · Barbara Schmidt🇩🇪 · Matthias Steinhauser🇩🇪

   We compute the decay rate of the Standard Model Higgs boson to bottom quarks to order $\alpha {\alpha }_s$. We apply the optical theorem and calculate the imaginary part of three-loop corrections to the Higgs boson propagator using asymptotic expansions in appropriately chosen mass ratios. The corrections of order $\alpha {\alpha }_s$ are of the same order of magnitude as the $\mathcal{O}({\alpha }_s^3)$ QCD corrections but have the opposite sign.

   hep-phPLB(2015)·44 citations
9. 09*

   Exotic hadrons with heavy flavour or hidden flavour

   Jean-Marc Richard🇫🇷

   The molecular picture and the constituent-quark model of exotic hadrons are reviewed, with application to the states recently discovered in the hidden-charm and hidden beauty sectors, and to other configurations.

   hep-phNucl.Part.Phys.Proc.(2016)·0 citations
10. 10*

    Lineshape of the Higgs boson in future lepton colliders

    S. Jadach🇵🇱 · R.A. Kycia🇵🇱

    The effect of the photon emission (bremsstrahlung) in the cross section of the process of direct production of the Higgs boson in the future high luminosity electron and muon colliders is calculated. It was found that cross section at the top of the Higgs boson resonance peak is reduced by factor 0.347 for the electron collider and 0.548 for the muon collider. Machine spread of the centre of the mass energy of 4.2MeV (equal to the Higgs width) would reduce peak cross section further, by factor 0.170 and 0.256 (QED and energy spread) for electron and muon beams respectively. Possible uncertainties in the resummed QED calculations are discussed. Numerical results for the lineshape cross section including QED and many values of the machine energy spread are provided.

    hep-phhep-exPLB(2016)·40 citations
11. 11*

    Light Higgs Bosons in NMSSM at the LHC

    Monoranjan Guchait🇮🇳 · Jacky Kumar🇮🇳

    The next-to-minimal supersymmetric standard model (NMSSM) with an extended Higgs sector offers one of the Higgs boson as the Standard model (SM) like Higgs with a mass around 125 GeV along with other Higgs bosons with lighter and heavier masses and not excluded by any current experiments. At the LHC, phenomenology of these non SM like Higgs bosons is very rich and considerably different from the other supersymmetric models. In this work, assuming one of the Higgs bosons to be the SM like, we revisit the mass spectrum and couplings of non SM like Higgs bosons taking into consideration all existing constraints and identify the relevant region of parameter space. The discovery potential of these non SM like Higgs bosons, apart from their masses, is guided by their couplings with gauge bosons and fermions which are very much parameter space sensitive. We evaluate the rates of productions of these non SM like Higgs bosons at the LHC for a variety of decay channels in the allowed region of the parameter space. Although bb, {\tau}{\tau} decay modes appear to be the most promising, it is observed that for a substantial region of parameter space the two-photon decay mode has a remarkably large rate. In this work we emphasize that this diphoton mode can be exploited to find the NMSSM Higgs signal and can also be potential avenue to distinguish the NMSSM from the MSSM. In addition, we discuss briefly the various detectable signals of these non SM Higgs bosons at the LHC.

    hep-phhep-exInt.J.Mod.Phys.A(2016)·26 citations
12. 12*

    Higgs pair signal enhanced in the 2HDM with two degenerate 125 GeV Higgs bosons

    Xiao-Fang Han🇨🇳 · Lei Wang🇪🇸 · Jin Min Yang🇨🇳

    We discuss a scenario of the type-II 2HDM in which the $b\bar{b}\gamma \gamma$ rate of the Higgs pair production is enhanced due to the two nearly degenerate 125 GeV Higgs bosons ($h$, $H$). Considering various theoretical and experimental constraints, we figure out the allowed ranges of the trilinear couplings of these two Higgs bosons and calculate the signal rate of $b\bar{b}\gamma \gamma$ from the productions of Higgs pairs ($hh$, $hH$, $HH$) at the LHC. We find that in the allowed parameter space some trilinear Higgs couplings can be larger than the SM value by an order and the production rate of $b\bar{b}\gamma \gamma$ can be greatly enhanced. We also consider a "decoupling" benchmark point where the light CP-even Higgs has a SM-like cubic self-coupling while other trilinear couplings are very small. With a detailed simulation on the $b\bar{b}\gamma \gamma$ signal and backgrounds, we find that in such a "decoupling" scenario the $hh$ and $hH$ channels can jointly enhance the statistical significance to 5$\sigma$ at 14 TeV LHC with an integrated luminosity of 3000 fb${}^{-1}$.

    hep-phMod.Phys.Lett.A(2016)·9 citations
13. 13*

    Phenomenology of $P_c(4380{)}^{+}$, $P_c(4450{)}^{+}$ and related states

    T. J. Burns🇬🇧

    The $P_c(4380{)}^{+}$ and $P_c(4450{)}^{+}$ states recently discovered at LHCb have masses close to several relevant thresholds, which suggests they can be described in terms of meson-baryon degrees of freedom. This article explores the phenomenology of these states, and their possible partners, from this point of view. Competing models can be distinguished by the masses of the neutral partners which have yet to be observed, and the existence or otherwise of further partners with different isospin, spin, and parity. Future experimental studies in different decay channels can also discriminate among models, using selection rules and algebraic relations among decays. Among the several possible meson-baryon pairs which could be important, one implies that the states are mixtures of isospins 1/2 and 3/2, with characteristic signatures in production and decay. A previous experimental study of a Cabibbo-suppressed decay showed no evidence for the states, and further analysis is required to establish the significance of this non-observation. Several intriguing similarities suggest that $P_c(4450{)}^{+}$ is related to the $X(3872)$ meson.

    hep-phhep-exEPJA(2015)·155 citations
14. 14*

    Light Stops in a minimal U(1)x extension of the MSSM

    R. M. Capdevilla🇺🇸 · A. Delgado🇺🇸 · A. Martin🇺🇸

    In order to reproduce the measured mass of the Higgs boson mh = 125GeV in the minimal supersymmetric standard model, one usually has to rely on heavy stops, increasing the fine tuning of the electroweak scale. By introducing a new gauge sector, the Higgs mass gets a tree-level contribution via a non-decoupling D-term, and mh = 125 GeV can be obtained with lighter stops. In this paper, we study the values of the stops masses needed to achieve the correct Higgs mass in a setup where the gauge group is extended by a single U(1)x interaction. We derive the experimental limits on the mass of the Z' gauge boson in this setup, then discuss how the stops masses vary as a function of the free parameters introduced by the new sector. We find that the correct Higgs mass can be reproduced with stops in a region between 700 - 800 GeV and a Z' resonance close to the 2.5 TeV bound from the run-I of the LHC, or in a higher region 800 - 900 GeV if the Z' resonance is heavier (3.1 TeV). This region of parameter space will be quickly accessible at run-II of the LHC, and we discuss the impact of the projected run-II bounds on the U(1)x parameter space. We also discuss the phenomenology of the Higgs-like particles introduced to break U(1)x and conclude their effects are too small to be detected at current colliders.

    hep-phPRD(2015)·9 citations
15. 15*

    Matter-coupled de Sitter Supergravity

    Renata Kallosh🇺🇸

    De Sitter supergravity describes interaction of supergravity with general chiral and vector multiplets as well as one nilpotent chiral multiplet. The extra universal positive term in the potential due to the nilpotent multiplet, corresponding to the anti-D3 brane in string theory, supports de Sitter vacua in these supergravity models. In the flat space limit these supergravity models include the Volkov-Akulov model with a non-linearly realized supersymmetry. The rules for constructing pure de Sitter supergravity action are generalized here in presence of other matter multiplets. We present a strategy to derive the complete closed form general supergravity action with a given Kahler potential $K$, superpotential $W$ and vector matrix $f_{AB}$ interacting with a nilpotent chiral multiplet. It has the potential $V=e^K(|F^2|+|DW{|}^2-3|W{|}^2)$, where $F$ is a necessarily non-vanishing value of the auxiliary field of the nilpotent multiplet. De Sitter vacua are present under simple condition that $|F^2|-3|W{|}^2>0$. A complete explicit action in the unitary gauge is presented.

    ↳ hep-thgr-qchep-phTheor.Math.Phys.(2016)·41 citations
16. 16*

    De Sitter Supergravity Model Building

    Renata Kallosh🇺🇸 · Timm Wrase🇦🇹

    We present the explicit de Sitter supergravity action describing the interaction of supergravity with an arbitrary number of chiral and vector multiplets as well as one nilpotent chiral multiplet. The action has a non-Gaussian dependence on the auxiliary field of the nilpotent multiplet, however, it can be integrated out for an arbitrary matter-coupled supergravity. The general supergravity action with a given Kahler potential $K$, superpotential $W$ and vector matrix $f_{AB}$ interacting with a nilpotent chiral multiplet consists of the standard supergravity action defined by $K$, $W$ and $f_{AB}$ where the scalar in the nilpotent multiplet has to be replaced by a bilinear combination of the fermion in the nilpotent multiplet divided by the Gaussian value of the auxiliary field. All additional contributions to the action start with terms quartic and higher order in the fermion of the nilpotent multiplet. These are given by a simple universal closed form expression.

    ↳ hep-thgr-qchep-phPRD(2015)·57 citations
17. 17*

    Simulated Milky Way analogues: implications for dark matter indirect searches

    F. Calore🇳🇱 · N. Bozorgnia🇳🇱 · M. Lovell🇳🇱 · G. Bertone🇳🇱 · M. Schaller🇬🇧 · C. S. Frenk🇬🇧 · R. A. Crain🇬🇧 · J. Schaye🇳🇱 · T. Theuns🇬🇧 · J. W. Trayford🇬🇧

    We study high-resolution hydrodynamic simulations of Milky Way type galaxies obtained within the "Evolution and Assembly of GaLaxies and their Environments" (EAGLE) project, and identify the those that best satisfy observational constraints on the Milky Way total stellar mass, rotation curve, and galaxy shape. Contrary to mock galaxies selected on the basis of their total virial mass, the Milky Way analogues so identified consistently exhibit very similar dark matter profiles inside the solar circle, therefore enabling more accurate predictions for indirect dark matter searches. We find in particular that high resolution simulated haloes satisfying observational constraints exhibit, within the inner few kiloparsecs, dark matter profiles shallower than those required to explain the so-called Fermi GeV excess via dark matter annihilation.

    ↳ astro-ph.GAastro-ph.COhep-phJCAP(2015)·58 citations
18. 18*

    Dark matter annihilation radiation in hydrodynamic simulations of Milky Way haloes

    Matthieu Schaller (1)🇬🇧 · Carlos S. Frenk (1)🇬🇧 · Tom Theuns (1)🇬🇧 · Francesca Calore (2)🇳🇱 · Gianfranco Bertone (2)🇳🇱 · Nassim Bozorgnia (2)🇳🇱 · Robert A. Crain (3)🇬🇧 · Azadeh Fattahi (4)🇨🇦 · Julio F. Navarro (4)🇨🇦 · Till Sawala (1)🇬🇧 · Joop Schaye (5) ((1) ICC, Durham University, (2) GRAPPA/Amsterdam, (3) Liverpool John Moores, (4) University of Victoria, (5) Leiden Observatory)🇳🇱

    We obtain predictions for the properties of cold dark matter annihilation radiation using high resolution hydrodynamic zoom-in cosmological simulations of Milky Way-like galaxies (APOSTLE project) carried out as part of the "Evolution and Assembly of GaLaxies and their Environments" (EAGLE) programme. Galactic halos in the simulation have significantly different properties from those assumed in the "standard halo model" often used in dark matter detection studies. The formation of the galaxy causes a contraction of the dark matter halo, whose density profile develops a steeper slope than the Navarro-Frenk-White (NFW) profile between $r\approx 1.5$ kpc and $r\approx 10$ kpc. At smaller radii, $r\lesssim 1.5$ kpc, the halos develop a flatter than NFW slope. This unexpected feature may be specific to our particular choice of subgrid physics model but nevertheless the dark matter density profiles agree within 30% as the mass resolution is increased by a factor 150. The inner regions of the halos are almost perfectly spherical (axis ratios $b/a>0.97$ within $r=1$ kpc) and there is no offset larger than 45 pc between the centre of the stellar distribution and the centre of the dark halo. The morphology of the predicted dark matter annihilation radiation signal is in broad agreement with $\gamma$-ray observations at large Galactic latitudes ($b\gtrsim 3^{\circ }$). At smaller angles, the inferred signal in one of our four galaxies is similar to that which is observed but it is significantly weaker in the other three.

    ↳ astro-ph.COastro-ph.GAhep-phMNRAS(2016)·50 citations
19. 19*

    Observation of scaling in the dynamics of a strongly quenched quantum gas

    Eike Nicklas🇩🇪 · Markus Karl🇩🇪 · Moritz Höfer🇩🇪 · Aisling Johnson🇫🇷 · Wolfgang Muessel🇩🇪 · Helmut Strobel🇩🇪 · Jiří Tomkovič🇩🇪 · Thomas Gasenzer🇩🇪 · Markus K. Oberthaler🇩🇪

    We report on the experimental observation of scaling in the time evolution following a sudden quench into the vicinity of a quantum critical point. The experimental system, a two-component Bose gas with coherent exchange between the constituents, allows for the necessary high level of control of parameters as well as the access to time-resolved spatial correlation functions. The theoretical analysis reveals that when quenching the system close to the critical point, the energy introduced by the quench leads to a short-time evolution exhibiting crossover reminiscent of the finite-temperature critical properties in the system's universality class. Observing the time evolution after a quench represents a paradigm shift in accessing and probing experimentally universal properties close to a quantum critical point and allows in a new way benchmarking of quantum many-body theory with experiments.

    ↳ cond-mat.quant-gashep-phnlin.PSquant-phPRL(2015)·84 citations
20. 20*

    Exploring uncertainties in dark energy constraints using current observational data with Planck 2015 distance priors

    Yun Wang🇺🇸 · Mi Dai🇺🇸

    We present the distance priors that we have derived from the 2015 Planck data, and use these in combination with the latest observational data from Type Ia Supernovae (SNe Ia) and galaxy clustering, to explore the systematic uncertainties in dark energy constraints. We use the Joint Lightcurve Analysis (JLA) set of 740 SNe Ia, galaxy clustering measurements of H(z)s and D_A(z)/s (where s is the sound horizon at the drag epoch) from the Sloan Digital Sky Survey (SDSS) at z=0.35 and z=0.57 (BOSS DR12). We find that the combined dark energy constraints are insensitive to the assumptions made in the galaxy clustering measurements (whether they are for BAO only or marginalized over RSD), which indicates that as the analysis of galaxy clustering data becomes more accurate and robust, the systematic uncertainties are reduced. On the other hand, we find that flux-averaging SNe Ia at z>= 0.5 significantly tightens the dark energy constraints, and excludes a flat universe with a cosmological constant at 68% confidence level, assuming a dark energy equation of state linear in the cosmic scale factor. Flux-averaging has the most significant effect when we allow dark energy density function X(z) to be a free functions given by the cubic spline of its value at z=0, 1/3, 2/3, 1; the measured X(z) deviates from a cosmological constant at more than 95% confidence level for 0.4 < z < 0.7. Since flux-averaging reduces the bias in the SN distance measurements, this may be an indication that we have arrived in the era when the SN distance measurements are limited by systematic uncertainties.

    ↳ astro-ph.COhep-phPRD(2016)·62 citations
21. 21*

    Indication of change of phase in high-multiplicity proton-proton events at LHC in String Percolation Model

    I. Bautista🇲🇽 · A. Fernandez Téllez🇲🇽 · Premomoy Ghosh🇮🇳

    We analyze high multiplicity proton-proton ($pp$) collision data in the framework of the String Percolation Model (SPM) that has been successful in describing several phenomena of multiparticle production, including the signatures of recent discovery of strongly interacting partonic matter, the Quark Gluon Plasma (QGP), in relativistic heavy-ion collisions. Our study in terms of the ratio of shear viscosity and entropy density ($\eta /s$) and the (LQCD) predicted signature of QCD change of phase, in terms of effective number of degrees of freedom ($ϵ/T^4$), reiterates the possibility of strongly interacting collective medium in these events.

    ↳ nucl-thhep-phnucl-exPRD(2015)·32 citations
22. 22*

    About Monopoles in QCD

    Adriano Di Giacomo🇮🇹

    The hypothesis is analysed that the monopoles condensing in QCD vacuum to make it a dual superconductor are classical solutions of the equations of motion.

    ↳ hep-lathep-phhep-thNucl.Part.Phys.Proc.(2016)·4 citations
23. 23*

    From "Dirac combs" to Fourier-positivity

    Bertrand G. Giraud🇫🇷 · Robi Peschanski (IPhT, Saclay)🇫🇷

    Motivated by various problems in physics and applied mathematics, we look for constraints and properties of real Fourier-positive functions, i.e. with positive Fourier transforms. Properties of the "Dirac comb" distribution and of its tensor products in higher dimensions lead to Poisson resummation, allowing for a useful approximation formula of a Fourier transform in terms of a limited number of terms. A connection with the Bochner theorem on positive definiteness of Fourier-positive functions is discussed. As a practical application, we find simple and rapid analytic algorithms for checking Fourier-positivity in 1- and (radial) 2-dimensions among a large variety of real positive functions. This may provide a step towards a classification of positive positive-definite functions.

    ↳ math-phhep-phhep-thmath.MPActa Phys.Polon.B(2016)·3 citations
24. 24*

    Search for dark matter in the hidden-photon sector with a large spherical mirror

    The FUNK Experiment: Darko Veberič (1)🇩🇪 · Kai Daumiller (1)🇩🇪 · Babette Döbrich (2)🇨🇭 · Ralph Engel (1)🇩🇪 · Joerg Jaeckel (3)🇩🇪 · Marek Kowalski (4 and 5)🇩🇪 · Axel Lindner (4)🇩🇪 · Hermann-Josef Mathes (1)🇩🇪 · Javier Redondo (6)🇪🇸 · Markus Roth (1)🇩🇪 · Christoph M. Schäfer (1)🇩🇪 · Ralf Ulrich (1) ((1) Institute for Nuclear Physics, Karlsruhe Institute of Technology (KIT), Germany, (2) Physics Department, CERN, Geneva, Switzerland, (3) Institute for Theoretical Physics, Heidelberg University, Germany, (4) Deutsches Elektronen Synchrotron DESY, Hamburg, Germany, (5) Department of Physics, Humboldt University, Berlin, Germany, (6) Department of Theoretical Physics, University of Zaragoza, Spain)🇩🇪

    If dark matter consists of hidden-sector photons which kinetically mix with regular photons, a tiny oscillating electric-field component is present wherever we have dark matter. In the surface of conducting materials this induces a small probability to emit single photons almost perpendicular to the surface, with the corresponding photon frequency matching the mass of the hidden photons. We report on a construction of an experimental setup with a large ~14 m2 spherical metallic mirror that will allow for searches of hidden-photon dark matter in the eV and sub-eV range by application of different electromagnetic radiation detectors. We discuss sensitivity and accessible regions in the dark matter parameter space.

    ↳ astro-ph.IMhep-exhep-phphysics.ins-detPoS(2016)·14 citations
25. 25*

    Masses of $D$ mesons, $D_s$ mesons and charmonium states from twisted mass lattice QCD

    Martin Kalinowski🇩🇪 · Marc Wagner🇩🇪

    We compute masses of $D$ mesons, $D_s$ mesons and charmonium states using Wilson twisted mass lattice QCD. We present results for spin $J=0,1,2,3$, parity $\mathcal{P}=-,+$ and in case of charmonium also charge conjugation $\mathcal{C}=-,+$. Computations are based on quark-antiquark creation operators and performed at three different unphysically heavy $u/d$ quark masses allowing an extrapolation to the physical $u/d$ quark mass. Within combined statistical and systematic errors, which are around $2\%\dots 3\%$, our results agree with available experimental results. Particular focus is put on the $J^{\mathcal{P}}=1^{+}$ mesons $D_1(2430)$ and $D_1(2420)$. We separate and classify these close-by states according to the total angular momentum of their light degrees of freedom, $j\approx 1/2$ and $j\approx 3/2$. This is a first important step to study decays $B^{(\ast )}\to D_1+l+\nu$, for which a long-standing conflict between theory and experiment exists.

    ↳ hep-lathep-exhep-phPRD(2015)·49 citations
26. 26*

    Experiments testing macroscopic quantum superpositions must be slow

    Andrea Mari🇮🇹 · Giacomo De Palma🇮🇹 · Vittorio Giovannetti🇮🇹

    We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. We give a solution to the paradox which is based on the following fundamental principle: any local experiment, discriminating a coherent superposition from an incoherent statistical mixture, necessarily requires a minimum time proportional to the mass (or charge) of the system. For a charged particle, we consider two examples of such experiments, and show that they are both consistent with the previous limitation. In the first, the measurement requires to accelerate the charge, that can entangle with the emitted photons. In the second, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field. On the other hand, when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations and for the possibility of entangling a particle with quantum gravitational radiation.

    ↳ quant-phgr-qchep-phhep-thSci.Rep.(2016)·67 citations
27. 27*

    Tomographic Constraints on High-Energy Neutrinos of Hadronuclear Origin

    Shin'ichiro Ando🇳🇱 · Irene Tamborra🇳🇱 · Fabio Zandanel🇳🇱

    Mounting evidence suggests that the TeV-PeV neutrino flux detected by the IceCube telescope has mainly an extragalactic origin. If such neutrinos are primarily produced by a single class of astrophysical sources via hadronuclear ($pp$) interactions, a similar flux of gamma-ray photons is expected. For the first time, we employ tomographic constraints to pinpoint the origin of the IceCube neutrino events by analyzing recent measurements of the cross correlation between the distribution of GeV gamma rays, detected by the Fermi satellite, and several galaxy catalogs in different redshift ranges. We find that the corresponding bounds on the neutrino luminosity density are up to one order of magnitude tighter than those obtained by using only the spectrum of the gamma-ray background, especially for sources with mild redshift evolution. In particular, our method excludes any hadronuclear source with a spectrum softer than $E^{-2.1}$ as a main component of the neutrino background, if its evolution is slower than $(1+z{)}^3$. Starburst galaxies, if able to accelerate and confine cosmic rays efficiently, satisfy both spectral and tomographic constraints.

    ↳ astro-ph.HEastro-ph.COhep-phPRL(2015)·51 citations

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