Thu·Aug 20, 2015Thursday·August 20, 2015

1. 01*

   Phenomenological neutron star equations of state: 3-window modeling of QCD matter

   Toru Kojo🇺🇸

   We discuss the 3-window modeling of cold, dense QCD matter equations of state at density relevant to neutron star properties. At low baryon density, n_B < ~ 2n_s (n_s: nuclear saturation density), we utilize purely hadronic equations of state that are constrained by empirical observations at density n_B ~ n_s and neutron star radii. At high density, n_B > ~ 5n_s, we use the percolated quark matter equations of state which must be very stiff to pass the two-solar mass constraints. The intermediate domain at 2 < n_B/n_s < 5 is described as neither purely hadronic nor percolated quark matter, and the equations of state are inferred by interpolating hadronic and percolated quark matter equations of state. Possible forms of the interpolation are severely restricted by the condition on the (square of) speed of sound, 0 < c_s^2 < 1. The characteristics of the 3-window equation of state are compared with those of conventional hybrid and self-bound quark matters. Using a schematic quark model for the percolated domain, it is argued that the two-solar mass constraint requires the model parameters to be as large as their vacuum values, indicating that the gluon dynamics remains strongly non-perturbative to n_B ~ 10n_s. The hyperon puzzle is also briefly discussed in light of quark descriptions.

   hep-phastro-ph.HEnucl-thEPJA(2016)·45 citations
2. 02*

   Scalar Singlet Dark Matter and Gamma Lines

   Michael Duerr🇩🇪 · Pavel Fileviez Perez🇩🇪 · Juri Smirnov🇩🇪

   We point out the possibility to test the simplest scalar dark matter model at gamma-ray telescopes. We discuss the relevant constraints and show the predictions for direct detection, gamma line searches and LHC searches. Since the final state radiation processes are suppressed by small Yukawa couplings one could observe the gamma lines from dark matter annihilation.

   hep-phastro-ph.COhep-exPLB(2015)·45 citations
3. 03*

   The distribution of linearly polarized gluons and elliptic azimuthal anisotropy in DIS dijet production at high energy

   Adrian Dumitru🇺🇸 · Tuomas Lappi🇫🇮 · Vladimir Skokov🇺🇸

   We determine the distribution of linearly polarized gluons of a dense target at small $x$ by solving the B-JIMWLK rapidity evolution equations. From these solutions we estimate the amplitude of $\sim \cos 2\varphi$ azimuthal asymmetries in DIS dijet production at high energies. We find sizeable long-range in rapidity azimuthal asymmetries with a magnitude in the range of $v_2=⟨\cos 2\varphi ⟩\sim 10\%$.

   hep-phPRL(2015)·117 citations
4. 04*

   TeV Lepton Number Violation: From Neutrinoless Double Beta Decay to the LHC

   Tao Peng🇺🇸 · Michael J. Ramsey-Musolf🇺🇸 · Peter Winslow🇺🇸

   We analyze the sensitivity of next-generation tonne-scale neutrinoless double $\beta$-decay ($0\nu \beta \beta$) experiments and searches for same-sign di-electrons plus jets at the Large Hadron Collider to TeV scale lepton number violating interactions. Taking into account previously unaccounted for physics and detector backgrounds at the LHC, renormalization group evolution, and long-range contributions to $0\nu \beta \beta$ nuclear matrix elements, we find that the reach of tonne-scale $0\nu \beta \beta$ generally exceeds that of the LHC. However, for a range of heavy particle masses near the TeV scale, the high luminosity LHC and tonne-scale $0\nu \beta \beta$ may provide complementary probes.

   hep-phnucl-thPRD(2016)·49 citations
5. 05*

   Semitauonic B Decay Anomaly

   E. C. F. S. Fortes🇧🇷 · Shmuel Nussinov🇮🇱

   The anomalously large experimentally measured ratios of the semitauonic decay $B\to D^{(\ast )}+\tau +\nu$ and the corresponding semileptonic $B\to D^{\ast }+\text{l}+{\bar{\nu }}_l$ disagree with the predictions of the standard E.W + QCD model(S.M). We briefly comment on this disagreement and on possible new physics explanations which are rather constrained and difficult to implement.

   hep-phPRD(2016)·3 citations
6. 06*

   Vector dark matter at the LHC

   Jason Kumar🇺🇸 · Danny Marfatia🇺🇸 · David Yaylali🇺🇸

   We consider monojet searches at the Large Hadron Collider (LHC) for spin-1 dark matter that interacts with quarks through a contact operator. If the dark matter particles are produced with longitudinal polarizations, then the production matrix element is enhanced by factors of the energy. We show that this particularly effective search strategy can test models for which the energy suppression scale of the operator is as large as 10^5 TeV. As such, these searches can probe a large class of models for which the contact-operator approximation is valid. We find that for contact operators that permit velocity-independent dark matter-nucleon scattering, LHC monojet searches for spin-1 dark matter are competitive with or far surpass direct-detection searches depending on whether the scattering is spin independent or spin dependent, respectively.

   hep-phastro-ph.COhep-exPRD(2015)·22 citations
7. 07*

   Solving the NLO BK equation in coordinate space

   T. Lappi🇫🇮 · H. Mäntysaari🇫🇮

   We present results from a numerical solution of the next-to-leading order (NLO) Balitsky-Kovchegov (BK) equation in coordinate space in the large Nc limit. We show that the solution is not stable for initial conditions that are close to those used in phenomenological applications of the leading order equation. We identify the problematic terms in the NLO kernel as being related to large logarithms of a small parent dipole size, and also show that rewriting the equation in terms of the "conformal dipole" does not remove the problem. Our results qualitatively agree with expectations based on the behavior of the linear NLO BFKL equation.

   hep-phnucl-thPoS(2015)·0 citations
8. 08*

   Breaking down the entire W boson spin observables from its decay

   J. A. Aguilar-Saavedra🇪🇸 · J. Bernabeu🇪🇸

   We discuss the eight independent spin observables for the $W$ boson in terms of its vector and tensor polarizations and identify the angular distributions and asymmetries able to separate them in collider experiments. The results are applied to the study of polarized top quark decays and diboson resonances. These novel observables are of great value for disentangling new physics mechanisms in $W$ boson production.

   hep-phhep-exPRD(2016)·77 citations
9. 09*

   Enhancement of the lepton flavor violating Higgs boson decay rates from SUSY loops in the inverse seesaw model

   E. Arganda🇪🇸 · M.J. Herrero🇪🇸 · X. Marcano🇪🇸 · C. Weiland🇪🇸

   In this article we study the full one-loop SUSY contributions to the lepton flavor violating Higgs decay $h\to \tau \bar{\mu }$, within the context of the supersymmetric inverse sesaw model. We assume that both the right-handed neutrino masses, $M_R$, and their supersymmetric partner masses, $m_{{\tilde{\nu }}_R}$, are not far from the interesting $\mathcal{O}(\mathrm{TeV})$ energy scale, and we work with scenarios with large neutrino Yukawa couplings that transmit large lepton flavor violating effects. By exploring the behavior with the most relevant parameters, mainly $M_R$, $m_{{\tilde{\nu }}_R}$ and the trilinear sneutrino coupling $A_{\nu }$, we will look for regions of the parameter space where the enhancement of $\mathrm{BR}(h\to \tau \bar{\mu })$ is large enough to reach values at the percent level, which could explain the excess recently reported by CMS and ATLAS at the CERN Large Hadron Collider.

   hep-phPRD(2016)·79 citations
10. 10*

    Forward jets and large rapidity gaps

    Mario Campanelli🇬🇧

    Hadronic jets are extremely abundant at the LHC, and testing QCD in various corners of phase-space is important to understand backgrounds and some specific signatures of new physics. In this article, various measurements aiming at probing QCD in configurations where the theory modeling become challenging are presented. Azimuthal angle de-correlations are sensitive to hard as well as soft QCD emission, and in most of the events jets are produced in a back-to-back configuration. Events where jets have a large rapidity separation are also rare, and those without additional radiation between the jets are exponentially suppressed. The modeling of radiation between very forward and backward jets is complicated, and may require theoretical tools different with respect to those normally used for central, high-pt events. Observables can be created that are sensitive to all these effects, like the study of azimuthal angle de-correlations between events where the two leading jets have large rapidity separations. The two general-purpose detectors of the LHC have measured these observables, and for some of them interesting deviations with respect to the most commonly used theoretical models are observed.

    hep-phInt.J.Mod.Phys.A(2015)·4 citations
11. 11*

    Diagrams and Parastatistical Factors for Cascade Emission of a Pair of Paraparticles

    Charles A. Nelson🇺🇸 · Margarita Kraynova🇺🇸 · Calvin S. Mera🇺🇸 · Alanna M. Shapiro🇺🇸

    The empirical absence to date of particles obeying parastatistics in high energy collider experiments might be due to their large masses, weak scale couplings, and lack of gauge couplings. Paraparticles of order p=2 must be pair produced, so the lightest such particles are absolutely stable and so are excellent candidates to be associated with dark matter and/or dark energy. If there is a portal to such particles, from a new scalar A1 boson they might be cascade emitted as a pair of para-Majorana neutrinos as in A1 ---> A2 para-nu para-nu or as a pair of neutral spin-zero paraparticles such as in A1 ---> A2 para-A para-B, where para-B is the anti-paraparticle to para-A. In this paper, for an assumed supersymmetric-like "statistics portal" Lagrangian, the associated connected tree diagrams and their parastatistical factors are obtained for the case of order p=2 parastatistics. These factors are compared with the corresponding statistical factors for the analogous emission of a non-degenerate or a 2-fold degenerate pair which obey normal statistics. This shows that diagrams, and diagrammatic thinking, can be use in perturbatively analyzing paraparticle processes. The parastatistical factor associated with each diagram does require explicit calculation.

    hep-phhep-exhep-thPRD(2016)·10 citations
12. 12*

    First Limits on the Dark Matter Cross Section with the HAWC Observatory

    Megan Longo Proper🇺🇸 · J. Patrick Harding🇺🇸 · Brenda Dingus (for the HAWC Collaboration)🇺🇸

    The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field-of-view observatory sensitive to 100 GeV - 100 TeV gamma rays and cosmic rays. The HAWC observatory is also sensitive to diverse indirect searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Among the most promising classes of objects for the indirect detection of dark matter are dwarf spheroidal galaxies. These objects are expected to have few astrophysical sources of gamma rays but high dark matter content, making them ideal candidates for an indirect dark matter detection with gamma rays. Here we present independent limits on the annihilation cross section for 14 dwarf spheroidal galaxies within the HAWC field-of-view, as well as their combined limit. These are the first limits on the annihilation cross section using data collected with HAWC.

    ↳ astro-ph.HEastro-ph.COhep-phPoS(2016)·13 citations
13. 13*

    Using spectator distributions to measure the initial geometry fluctuation

    Md Nasim🇺🇸

    A study of eccentricity (${\epsilon }_n$) fluctuations and its possible impact on final state momentum anisotropy ($v_n$) for symmetric collisions are presented in the framework of Glauber model. Effect of fluctuations of nucleon's position on the initial geometry has been studied using a new method, where the difference between oppositely moving spectators is taken as a measurement of eccentricity fluctuations. This study shows that higher harmonics ($n$ =3, 4 and 5) of eccentricity are less sensitive to fluctuations in transverse plane compared to the 2${}^{nd}$ harmonic. Position fluctuations in transverse plane will increase ${\epsilon }_2$ and hence possibly $v_2$ for the most central nucleus-nucleus collisions. For semi-central and peripheral collisions, the fluctuations have opposite effect, it deceases the eccentricity ${\epsilon }_2$. The fluctuation of initial geometry can be studied in collider experiments by studying the spectator distribution on the both sides of the beam.

    ↳ nucl-thhep-phnucl-exIJMPE(2015)·0 citations
14. 14*

    A non-perturbative estimate of the heavy quark momentum diffusion coefficient

    A. Francis🇨🇦 · O. Kaczmarek🇩🇪 · M. Laine🇨🇭 · T. Neuhaus🇩🇪 · H. Ohno🇺🇸

    We estimate the momentum diffusion coefficient of a heavy quark within a pure SU(3) plasma at a temperature of about 1.5Tc. Large-scale Monte Carlo simulations on a series of lattices extending up to 192^3*48 permit us to carry out a continuum extrapolation of the so-called colour-electric imaginary-time correlator. The extrapolated correlator is analyzed with the help of theoretically motivated models for the corresponding spectral function. Evidence for a non-zero transport coefficient is found and, incorporating systematic uncertainties reflecting model assumptions, we obtain kappa = (1.8 - 3.4)T^3. This implies that the "drag coefficient", characterizing the time scale at which heavy quarks adjust to hydrodynamic flow, is (1.8 - 3.4) (Tc/T)^2 (M/1.5GeV) fm/c, where M is the heavy quark kinetic mass. The results apply to bottom and, with somewhat larger systematic uncertainties, to charm quarks.

    ↳ hep-lathep-phPRD(2015)·180 citations
15. 15*

    Chiral Magnetic Effect and Anomalous Hall Effect in Antiferromagnetic Insulators with Spin-Orbit Coupling

    Akihiko Sekine🇯🇵 · Kentaro Nomura🇯🇵

    We search for dynamical magnetoelectric phenomena in three-dimensional correlated systems with spin-orbit coupling. We focus on the antiferromagnetic insulator phases where the dynamical axion field is realized by the fluctuation of the antiferromagnetic order parameter. It is shown that the dynamical chiral magnetic effect, an alternating current generation by magnetic fields, emerges due to the time dependences of the order parameter such as antiferromagnetic resonance. It is also shown that the anomalous Hall effect arises due to the spatial variations of the order parameter such as antiferromagnetic domain walls. Our study indicates that spin excitations in antiferromagnetic insulators with spin-orbit coupling can result in nontrivial charge responses. Moreover, observing the chiral magnetic effect and anomalous Hall effect in our system is equivalent to detecting the dynamical axion field in condensed matter.

    ↳ cond-mat.str-elcond-mat.mes-hallcond-mat.mtrl-scihep-lat+1PRL(2016)·45 citations
16. 16*

    Baryon as Impurity for Phase Transition in String Landscape

    Aya Kasai🇯🇵 · Yuichiro Nakai🇺🇸 · Yutaka Ookouchi🇯🇵

    We consider a decay of a false vacuum in flux compactifications of type IIB string theory and study a catalytic effect for a phase transition induced by a new type of impurities. We concentrate on the large N dual of a D5-brane/anti-D5-brane system which has a rich vacuum structure. We show that D3-branes wrapping the 3-cycles can form a dibaryon and make a bound state with a monopole. We find that these baryon-like objects can make the lifetime of the metastable vacuum shorter.

    ↳ hep-thhep-phJHEP(2016)·9 citations
17. 17*

    Quantum corrections in Higgs inflation: the Standard Model case

    Damien P. George🇬🇧 · Sander Mooij🇨🇱 · Marieke Postma🇳🇱

    We compute the one-loop renormalization group equations for Standard Model Higgs inflation. The calculation is done in the Einstein frame, using a covariant formalism for the multi-field system. All counterterms, and thus the betafunctions, can be extracted from the radiative corrections to the two-point functions; the calculation of higher n-point functions then serves as a consistency check of the approach. We find that the theory is renormalizable in the effective field theory sense in the small, mid and large field regime. In the large field regime our results differ slightly from those found in the literature, due to a different treatment of the Goldstone bosons.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2016)·69 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.