Tue·Aug 25, 2015Tuesday·August 25, 2015

1. 01*

   Dipole moments of charged leptons in the THDM-III with Textures

   M. Arroyo-Ureña🇲🇽 · Enrique Díaz🇲🇽

   We study the magnetic and weak magnetic dipole moments of charged leptons in the framework of the Two Higgs Doublet Model type III (THDM-III) with four zero textures. We first analyze the possibility that the discrepancy between the experimental measurements and the theoretical prediction of the muon anomalous magnetic dipole moment ($a_{\mu }$) in the Standard Model (SM) can be explained in the context of the model and then find values for the parameters of the THDM-III: neutral and charged Higgs boson masses ($m_H$, $m_{H^{\pm }}$), mixing angles ($\alpha ,\beta$), CP-violating angles ${\theta }_1,{\theta }_2$ and an additional parameter arising from the mass matrix (${\gamma }_f$), for which a correspondence between theory and experiment is possible. We use $a_{\mu }^{THDM-III}$ and current low energy processes $K-\bar{K}$ mixing, $B_s^0\to \mu \bar{\mu }$, $\tau \to \mu \mu \bar{\mu }$, $\mu \to ee\bar{e}$, $\tau \to \mu \gamma$, $\tau \to e\gamma$, $\mu \to e\gamma$, $b\to s\gamma$, $B\to D(D^{\ast })\tau \nu$ and the rare higgs decay $h\to \tau \mu$ in order to determine the allowed parameter space of THDM-III and from these we give a prediction for the magnetic and weak magnetic dipole moment of charged leptons, in particular of the $\tau$ lepton. The obtained magnetic dipole moment of the $\tau$ lepton is of the order of $\mathcal{O}(10^{-8}-10^{-7})$ and the weak magnetic is of the order $\mathcal{O}(10^{-10}-10^{-7})$.

   hep-phJ.Phys.G(2016)·11 citations
2. 02*

   Everything You Always Wanted to Know About Dark Matter Elastic Scattering Through Higgs Loops But Were Afraid to Ask

   Asher Berlin🇺🇸 · Dan Hooper🇺🇸 · Samuel D. McDermott🇺🇸

   We consider a complete list of simplified models in which Majorana dark matter particles annihilate at tree level to $hh$ or $hZ$ final states, and calculate the loop-induced elastic scattering cross section with nuclei in each case. Expressions for these annihilation and elastic scattering cross sections are provided, and can be easily applied to a variety of UV complete models. We identify several phenomenologically viable scenarios, including dark matter that annihilates through the $s$-channel exchange of a spin-zero mediator or through the $t$-channel exchange of a fermion. Although the elastic scattering cross sections predicted in this class of models are generally quite small, XENON1T and LZ should be sensitive to significant regions of this parameter space. Models in which the dark matter annihilates to $hh$ or $hZ$ can also generate a gamma-ray signal that is compatible with the excess observed from the Galactic Center.

   hep-phPRD(2015)·12 citations
3. 03*

   Baryogenesis via Mesino Oscillations

   Akshay Ghalsasi🇺🇸 · David McKeen🇺🇸 · Ann E. Nelson🇺🇸

   We propose a new mechanism for baryogenesis at the 1-200 MeV scale. Enhancement of CP violation takes place via interference between oscillations and decays of mesinos--bound states of a scalar quark and antiquark and their CP conjugates. We present the mechanism in a simplified model with four new fundamental particles, with masses between 300 GeV and 10 TeV, and show that some of the experimentally allowed parameter space can give the observed baryon-to-entropy ratio.

   hep-phastro-ph.COPRD(2015)·19 citations
4. 04*

   Folded Supersymmetry with a Twist

   Timothy Cohen🇺🇸 · Nathaniel Craig🇺🇸 · Hou Keong Lou🇺🇸 · David Pinner🇺🇸

   Folded supersymmetry (f-SUSY) stabilizes the weak scale against radiative corrections from the top sector via scalar partners whose gauge quantum numbers differ from their Standard Model counterparts. This non-trivial pairing of states can be realized in extra-dimensional theories with appropriate supersymmetry-breaking boundary conditions. We present a class of calculable f-SUSY models that are parametrized by a non-trivial twist in 5D boundary conditions and can accommodate the observed Higgs mass and couplings. Although the distinctive phenomenology associated with the novel folded states should provide strong evidence for this mechanism, the most stringent constraints are currently placed by conventional supersymmetry searches. These models remain minimally fine-tuned in light of LHC8 data and provide a range of both standard and exotic signatures accessible at LHC13.

   hep-phJHEP(2016)·29 citations
5. 05*

   NLO Corrections to Double Higgs Production in the Higgs Singlet Model

   S. Dawson🇺🇸 · I. M. Lewis🇺🇸

   Higgs pair production at the LHC from gluon fusion is small in the Standard Model, but can be enhanced in models where a resonant enhancement is allowed. We examine the effect of a resonant contribution from a second scalar arising in a model with a gauge singlet scalar field in addition to the usual SU(2) scalar doublet, with mass up to $M_H$~600 GeV and discuss the interference effects in double Higgs production. We compute the NLO QCD corrections in the large $m_t$ limit and show that they can significantly distort kinematic distributions near the resonance peak.

   hep-phPRD(2015)·72 citations
6. 06*

   Two-Step Electroweak Baryogenesis

   Satoru Inoue🇺🇸 · Grigory Ovanesyan🇺🇸 · Michael J. Ramsey-Musolf🇺🇸

   We analyze electroweak baryogenesis during a two-step electroweak symmetry breaking transition, wherein the baryon asymmetry is generated during the first step and preserved during the second. Focusing on the dynamics of CP-violation required for asymmetry generation, we discuss general considerations for successful two-step baryogenesis. Using a concrete model realization, we illustrate in detail the viability of this scenario and the implications for present and future electric dipole moment (EDM) searches. We find that CP-violation associated with a partially excluded sector may yield the observed baryon asymmetry while evading present and future EDM constraints.

   hep-phhep-exnucl-exnucl-thPRD(2016)·102 citations
7. 07*

   Associated Production of Z_H and T in the Littlest Higgs Model at High Energy Linear e^-e^+ Collider

   Zerrin Kirca🇹🇷

   In this work we study associated production of heavy Z boson and heavy top quark in the framework of Littlest Higgs model at e^-e^+ colliders considering parameter space allowed by the electroweak precision measurments. According to the free parameters of the model the possibility of detecting of new heavy particles at sqrt{s}=3 TeV and yearly integrated luminosity of L=500 fb^-1 are discussed. We find that in a narrow range of the parameter space, s/s'=0.8/0.6,0.7, 0.4 <= x_L <= 0.6 and f <~1060 GeV, a statical significance of 5 sigma can be achieved. We also discuss constraints on masses of heavy top quark and heavy Z boson together with the mixing parameters s and x_L at sqrt{s}=3000 GeV.

   hep-ph2 citations
8. 08*

   Constraining Type I Seesaw with $A_4$ Flavor Symmetry From Neutrino Data and Leptogenesis

   Rupam Kalita🇮🇳 · Debasish Borah🇮🇳

   We study a type I seesaw model of neutrino masses within the framework of $A_4$ flavor symmetry. Incorporating the presence of both singlet and triplet flavons under $A_4$ symmetry, we construct the leptonic mass matrices involved in type I seesaw mechanism. We then construct the light neutrino mass matrix using the $3\sigma$ values of neutrino oscillation parameters keeping the presently undetermined parameters namely, the lightest neutrino mass $m_{\text{lightest}}$, one Dirac CP phase $\delta$ and two Majorana phases $\alpha ,\beta$ as free parameters. Comparing the mass matrices derived using $A_4$ parameters as well as light neutrino parameters, we then evaluate all the $A_4$ parameters in terms of light neutrino parameters. Assuming some specific vacuum alignments of $A_4$ triplet flavon field, we then numerically evaluate all the free parameters in the light neutrino sector, using which we also find out the remaining $A_4$ parameters. We then use the numerical values of these parameters to calculate baryon asymmetry through the mechanism of leptogenesis. We not only constrain the $A_4$ vacuum alignments from the requirement of successful leptogenesis, but also constrain the free parameters in the light neutrino sector $(m_{\text{lightest}},\delta ,\alpha ,\beta )$ to certain range of values. These values can be tested in ongoing and future neutrino experiments providing a way to discriminate between different possible $A_4$ vacuum alignments discussed in this work.

   hep-phPRD(2015)·21 citations
9. 09*

   Determination of neutrino mass ordering in future ${}^{76}$Ge-based neutrinoless double-beta decay experiments

   Jue Zhang🇨🇳 · Shun Zhou🇨🇳

   Motivated by recent intensive experimental efforts on searching for neutrinoless double-beta decays, we perform a detailed analysis of the physics potential of the experiments based on ${}^{76}\mathrm{Ge}$. Assuming no signals, current and future experiments could place a $90\%$ lower limit on the half life $T_{1/2}^{0\nu }\gtrsim 4\times 10^{26}\mathrm{yr}$ and $T_{1/2}^{0\nu }\gtrsim 7\times 10^{27}\mathrm{yr}$, respectively. Then, how to report an evidence for neutrinoless double-beta decays is addressed by following the Bayesian statistical approach. For the first time, we present a quantitative description of experimental power to distinguish between normal and inverted neutrino mass orderings. Taking an exposure of $10^4\mathrm{kg}\cdot \mathrm{yr}$ and a background rate of $10^{-4}\mathrm{counts}/(\mathrm{keV}\cdot \mathrm{kg}\cdot \mathrm{yr})$, we find that a moderate evidence for normal neutrino mass ordering (i.e., with a Bayes factor $\mathcal{B}$ given by $\ln (\mathcal{B})\simeq 2.5$ or a probability about $92.3\%$ according to the Jeffreys scale) can be achieved if the true value of effective neutrino mass $m_{\beta \beta }^{}$ turns out to be below $0.01\mathrm{eV}$.

   hep-phhep-exPRD(2016)·10 citations
10. 10*

    Prompt charmonia production and polarization at LHC in the NRQCD with kt-factorization. Part I: psi(2S) meson

    S.P. Baranov🇷🇺 · A.V. Lipatov🇷🇺 · N.P. Zotov🇷🇺

    In the framework of kt-factorization approach, the production and polarization of prompt psi(2S) mesons in pp collisions at the LHC energies is studied. Our consideration is based on the non-relativistic QCD formalism for bound states and off-shell amplitudes for hard partonic subprocesses. The transverse momentum dependent (unintegrated) gluon densities in a proton were derived from Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were chosen in accordance with Kimber-Martin-Ryskin prescription. The non-perturbative color-octet matrix elements were first deduced from the fits to the latest CMS data on psi(2S) transverse momentum distributions and then applied to describe the ATLAS and LHCb data on psi(2S) production and polarization at 7 TeV. We perform the estimation of polarization parameters ${\lambda }_{\theta }$, ${\lambda }_{\varphi }$ and ${\lambda }_{\theta \varphi }$ which determine psi(2S) spin density matrix and demonstrate that taking into account the off-shellness of initial gluons in the color-octet contributions leads to unpolarized psi(2S) production at high transverse momenta, that is in qualitative agreement with the LHC data.

    hep-phEPJC(2015)·39 citations
11. 11*

    R-Parity Conserving Supersymmetric Extension of the Zee Model

    Shinya Kanemura🇯🇵 · Tetsuo Shindou🇯🇵 · Hiroaki Sugiyama🇯🇵

    We extend the Zee model, where tiny neutrino masses are generated at the one loop level, to a supersymmetric model with R-parity conservation. It is found that the neutrino mass matrix can be consistent with the neutrino oscillation data thanks to the nonholomorphic Yukawa interaction generated via one-loop diagrams of sleptons. We find a parameter set of the model, where in addition to the neutrino oscillation data, experimental constraints from the lepton flavor violating decays of charged leptons and current LHC data are also satisfied. In the parameter set, an additional CP-even neutral Higgs boson other than the standard-model-like one, a CP-odd neutral Higgs boson, and two charged scalar bosons are light enough to be produced at the LHC and future lepton colliders. If the lightest charged scalar bosons are mainly composed of the SU(2)_L-singlet scalar boson in the model, they would decay into e nu and mu nu with 50% of a branching ratio for each. In such a case, the relation among the masses of the charged scalar bosons and the CP-odd Higgs in the minimal supersymmetric standard model approximately holds with a radiative correction. Our model can be tested by measuring the specific decay patterns of charged scalar bosons and the discriminative mass spectrum of additional scalar bosons.

    hep-phPRD(2015)·6 citations
12. 12*

    ATLAS diboson excess from low scale supersymmetry breaking

    Christoffer Petersson🇧🇪 · Riccardo Torre🇮🇹

    We provide an interpretation of the recent ATLAS diboson excess in terms of a class of supersymmetric models in which the scale of supersymmetry (SUSY) breaking is in the few TeV range. The particle responsible for the excess is the scalar superpartner of the Goldstone fermion associated with SUSY breaking, the sgoldstino. This scalar couples strongly to the Standard Model vector bosons and weakly to the fermions, with all coupling strengths determined by ratios of soft SUSY breaking parameters over the SUSY breaking scale. Explaining the ATLAS excess selects particular relations and ranges for the gaugino masses, while imposing no constraints on the other superpartner masses. Moreover, this signal hypothesis predicts a rate in the $Z\gamma$ final state that is expected to be observable at the LHC Run II already with a few fb${}^{-1}$ of integrated luminosity.

    hep-phhep-exJHEP(2016)·25 citations
13. 13*

    Strong Decays of Charmed Baryons in Heavy Hadron Chiral Perturbation Theory: An Update

    Hai-Yang Cheng🇹🇼 · Chun-Khiang Chua🇹🇼

    We first give a brief overview of the charmed baryon spectroscopy and discuss their possible structure and spin-parity assignments in the quark model. With the new Belle measurement of the widths of ${\Sigma }_c(2455)$ and ${\Sigma }_c(2520)$ and the recent CDF measurement of the strong decays of ${\Lambda }_c(2595)$ and ${\Lambda }_c(2625)$, we give updated coupling constants in heavy hadron chiral perturbation theory. We find $g_2=0.565_{-0.024}^{+0.011}$ for $P$-wave transitions between $s$-wave and $s$-wave baryons, and $h_2$, one of the couplings responsible for $S$-wave transitions between $s$-wave and $p$-wave baryons, is extracted from ${\Lambda }_c(2595{)}^{+}\to {\Lambda }_c^{+}\pi \pi$ to be $0.63\pm 0.07$. It is substantially enhanced compared to the old value of order 0.437. With the help from the quark model, two of the couplings $h_{10}$ and $h_{11}$ responsible for $D$-wave transitions between $s$-wave and $p$-wave baryons are determined from ${\Sigma }_c(2880)$ decays. There is a tension for the coupling $h_2$ as its value extracted from ${\Lambda }_c(2595{)}^{+}\to {\Lambda }_c^{+}\pi \pi$ will imply ${\Xi }_c(2790{)}^0\to {\Xi }_c^{\prime }\pi$ and ${\Xi }_c(2815{)}^{+}\to {\Xi }_c^{\ast }\pi$ rates slightly above the current limits. It is conceivable that SU(3) flavor symmetry breaking can help account for the discrepancy.

    hep-phhep-exnucl-thPRD(2015)·105 citations
14. 14*

    Tau reconstruction methods at an electron-positron collider in the search for new physics

    Jinmian Li🇦🇺 · Anthony G. Williams🇦🇺

    By exploiting the relatively long lifetime of the tau lepton, we propose several novel methods for searching for new physics at an electron-positron collider. We consider processes that involve final states consisting of a tau lepton pair plus two missing particles. The mass and spin of the new physics particles can be measured in 3-prong tau decays. The tau polarization, which reflects the coupling to new physics, can be measured from the $\tau \to \pi \nu$ decay channel using the impact parameter distribution of the charged pion. We also discuss the corresponding backgrounds for these measurements, the next-to-leading order (NLO) effects, and the implications of finite detector resolution.

    hep-phhep-exPRD(2016)·3 citations
15. 15*

    Type-III two Higgs doublet model plus a pseudoscalar confronted with $h\to \mu \tau$, muon $g-2$ and dark matter

    Xuewen Liu🇨🇳 · Ligong Bian🇨🇳 · Xue-Qian Li🇨🇳 · Jing Shu🇨🇳

    In this work, we introduce an extra singlet pseudoscalar into the Type-III two Higgs doublet model (2HDM) which is supposed to solve a series of problems in the modern particle-cosmology. With existence of a light pseudoscalar, the $h\to \mu \tau$ excess measured at CMS and as well as the $(g-2{)}_{\mu }$ anomaly could be simultaneously explained within certain parameter spaces that can also tolerate the data on the flavor-violating processes $\tau \to \mu \gamma$ and Higgs decay gained at LHC. Within the same parameter spaces, the DM relic abundance is well accounted. Moreover, the recently observed Galactic Center gamma ray excess(GCE) is proposed to realize through dark matter(DM) pair annihilations, and in this work, the scenario of the annihilation being mediated by the pseudoscalar is also addressed.

    hep-phNPB(2016)·37 citations
16. 16*

    The Behaviour of the Green Function for the BFKL Pomeron with Running Coupling

    H. Kowalski🇩🇪 · L.N. Lipatov🇷🇺 · D.A. Ross🇬🇧

    We analyse here in LO the physical properties of the Green function solution for the BFKL equation. We show that the solution obeys the orthonormality conditions in the physical region and fulfills the completeness requirements. The unintegrated gluon density is shown to consists of a set of few poles with parameters which could be determined by comparison with the DIS data of high precision.

    hep-phEPJC(2016)·22 citations
17. 17*

    Improved analysis of the CLFV decay of muonic atoms ${\mu }^{-}{e}^{-}\to e^{-}{e}^{-}$

    Yuichi Uesaka🇯🇵 · Yoshitaka Kuno🇯🇵 · Joe Sato🇯🇵 · Toru Sato🇯🇵 · Masato Yamanaka🇯🇵

    Koike et al. proposed the charged lepton flavor violation (CLFV) decay of the muonic atom ${\mu }^{-}{e}^{-}\to e^{-}{e}^{-}$ as one of the promising processes to search for new physics beyond the standard model. It was found that the attractive interaction of leptons with the nucleus enhances the transition rate of the ${\mu }^{-}{e}^{-}\to e^{-}{e}^{-}$ process. We report on our improved analysis of this process by taking into account the distortion of the out-going electrons in the nuclear Coulomb potential and the relativistic treatment of the muon and the electrons. As results, we found significant enhancement of the transition rate. The transition rate for ${}^{208}$Pb becomes about 7 times larger than the previous estimation, which enhances the sensitivity of this process to discover the CLFV interaction. We also report on the energy spectrum of the out-going electron.

    hep-phPoS(2015)·4 citations
18. 18*

    Counting similarities between tetraquark and mesonic/gluonic operators

    Ming Chen🇨🇳 · Yong-Chang Huang🇨🇳

    After the study of the preclusion of exotic meson states in large-$N_c$ limit QCD, combining Weinberg's opposite proposal, we get different counting orders for a tetraquark operator to create or destroy an one-tetraquark state. Meanwhile, by comparing tetraquark operator with the mesonic and gluonic operators, we find that tetraquark operators are similar with mesonic and gluonic operators in the counting. Furthermore, we find a mixing of different kinds of operators.

    hep-phEPJA(2016)·1 citation
19. 19*

    ${\chi }_{cJ}$ Polarization in Polarized Proton-Proton Collisions at RHIC

    Gouranga C. Nayak🇺🇸

    We study inclusive ${\chi }_{cJ}$ production with definite polarizations in polarized proton-proton collisions at $\sqrt{s}$ = 200 GeV and 500 GeV at RHIC by using non-relativistic QCD (NRQCD) color-octet mechanism. We present results of rapidity distribution of ${\chi }_{c0}$, ${\chi }_{c1}$ and ${\chi }_{c2}$ production with specific polarizations in polarized p-p collisions at RHIC within the PHENIX detector acceptance range. We also present the corresponding results for the spin asymmetries.

    hep-phhep-exnucl-exnucl-thPhys.Part.Nucl.Lett.(2017)·2 citations
20. 20*

    Scalar Sector Phenomenology of Three-Loop Radiative Neutrino Mass Models

    Amine Ahriche (Jijel U. & ICTP, Trieste)🇩🇿 · Kristian L. McDonald (Sydney U.)🇦🇺 · Salah Nasri (United Arab Emirates U.)🇦🇪

    We perform a phenomenological study of the scalar sector of two models that generate neutrino mass at the three-loop level and contain viable dark matter candidates. Both models contain a charged singlet scalar and a larger scalar multiplet (triplet or quintuplet). We investigate the effect of the extra scalars on the Higgs mass and analyze the modifications to the triple Higgs coupling. The new scalars can give observable changes to the Higgs decay channel $h\to \gamma \gamma$ and, furthermore, we find that the electroweak phase transition becomes strongly first-order in large regions of parameter space.

    hep-phPRD(2015)·21 citations
21. 21*

    Rosetta: an operator basis translator for Standard Model effective field theory

    Adam Falkowski🇫🇷 · Benjamin Fuks🇫🇷 · Kentarou Mawatari🇧🇪 · Ken Mimasu🇬🇧 · Francesco Riva🇨🇭 · Verónica sanz🇬🇧

    We introduce Rosetta, a program allowing for the translation between different bases of effective field theory operators. We present the main functions of the program and provide an example of usage. One of the Lagrangians which Rosetta can translate into has been implemented into FeynRules, which allows Rosetta to be interfaced into various high-energy physics programs such as Monte Carlo event generators. In addition to popular bases choices, such as the Warsaw and Strongly Interacting Light Higgs bases already implemented in the program, we also detail how to add new operator bases into the Rosetta package. In this way, phenomenological studies using an effective field theory framework can be straightforwardly performed.

    hep-phhep-exEPJC(2015)·118 citations
22. 22*

    Consistency of Scalar Potentials from Quantum de Sitter Space

    José R. Espinosa🇪🇸 · Jean-François Fortin🇨🇦 · Maxime Trépanier🇨🇦

    Consistency of the unconventional view of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom requires that Coleman-De Luccia tunneling rates to vacua with negative cosmological constant should be interpreted as recurrences to low-entropy states. This demand translates into two constraints, or consistency conditions, on the scalar potential which are generically: 1) the distance in field space between the de Sitter vacuum and any other vacuum with negative cosmological constant must be of the order of the reduced Planck mass or larger and 2) the fourth root of the vacuum energy density of the de Sitter vacuum must be smaller than the fourth root of the typical scale of the scalar potential. These consistency conditions shed a different light on both outstanding hierarchy problems of the Standard Model of particle physics: the scale of electroweak symmetry breaking and the scale of the cosmological constant. Beyond the unconventional interpretation of quantum de Sitter space, we complete the analytic understanding of the thin-wall approximation of Coleman-De Luccia tunneling, extend its numerical analysis to generic potentials and discuss the role of gravity in stabilizing the Standard Model potential.

    ↳ hep-thhep-phPRD(2016)·21 citations
23. 23*

    Tagging Spallation Backgrounds with Showers in Water-Cherenkov Detectors

    Shirley Weishi Li🇺🇸 · John F. Beacom (Ohio State University)🇺🇸

    Cosmic-ray muons and especially their secondaries break apart nuclei ("spallation") and produce fast neutrons and beta-decay isotopes, which are backgrounds for low-energy experiments. In Super-Kamiokande, these beta decays are the dominant background in 6--18 MeV, relevant for solar neutrinos and the diffuse supernova neutrino background. In a previous paper, we showed that these spallation isotopes are produced primarily in showers, instead of in isolation. This explains an empirical spatial correlation between a peak in the muon Cherenkov light profile and the spallation decay, which Super-Kamiokande used to develop a new spallation cut. However, the muon light profiles that Super-Kamiokande measured are grossly inconsistent with shower physics. We show how to resolve this discrepancy and how to reconstruct accurate profiles of muons and their showers from their Cherenkov light. We propose a new spallation cut based on these improved profiles and quantify its effects. Our results can significantly benefit low-energy studies in Super-Kamiokande, and will be especially important for detectors at shallower depths, like the proposed Hyper-Kamiokande.

    ↳ physics.ins-detastro-ph.HEhep-exhep-phPRD(2015)·52 citations
24. 24*

    Inflation in a viscous fluid model

    Kazuharu Bamba🇯🇵 · Sergei D. Odintsov🇪🇸

    We explore a fluid description of the inflationary universe. In particular, we investigate a fluid model in which the equation of state (EoS) for a fluid includes bulk viscosity. We find that the three observables of inflationary cosmology: the spectral index of the curvature perturbations, the tensor-to-scalar ratio of the density perturbations, and the running of the spectral index, can be consistent with the recent Planck results. We also reconstruct the explicit EoS for a fluid from the spectral index of the curvature perturbations compatible with the Planck analysis. In the reconstructed models of a fluid, the tensor-to-scalar ratio of the density perturbations can satisfy the constraints obtained from the Planck satellite. The running of the spectral index can explain the Planck data. In addition, it is demonstrated that in the reconstructed models of a fluid, the graceful exit from inflation can be realized. Moreover, we show that the singular inflation can occur in a fluid model. Furthermore, we show that a fluid description of inflation can be equivalent to the description of inflation in terms of scalar field theories.

    ↳ gr-qcastro-ph.COhep-phhep-thEPJC(2016)·85 citations
25. 25*

    Exploring properties of high-density matter through remnants of neutron-star mergers

    Andreas Bauswein🇬🇷 · Nikolaos Stergioulas🇬🇷 · Hans-Thomas Janka🇩🇪

    Remnants of neutron-star mergers are essentially massive, hot, differentially rotating neutron stars, which are initially strongly oscillating. They represent a unique probe for high-density matter because the oscillations are detectable via gravitational-wave measurements and are strongly dependent on the equation of state. The impact of the equation of state is apparent in the frequency of the dominant oscillation mode of the remnant. For a fixed total binary mass a tight relation between the dominant postmerger frequency and the radii of nonrotating neutron stars exists. Inferring observationally the dominant postmerger frequency thus determines neutron star radii with high accuracy of the order of a few hundred meters. By considering symmetric and asymmetric binaries of the same chirp mass, we show that the knowledge of the binary mass ratio is not critical for this kind of radius measurements. We summarize different possibilities to deduce the maximum mass of nonrotating neutron stars. We clarify the nature of the three most prominent features of the postmerger gravitational-wave spectrum and argue that the merger remnant can be considered to be a single, isolated, self-gravitating object that can be described by concepts of asteroseismology. The understanding of the different mechanisms shaping the gravitational-wave signal yields a physically motivated analytic model of the gravitational-wave emission, which may form the basis for template-based gravitational-wave data analysis. We explore the observational consequences of a scenario of two families of compact stars including hadronic and quark stars. We find that this scenario leaves a distinctive imprint on the postmerger gravitational-wave signal. In particular, a strong discontinuity in the dominant postmerger frequency as function of the total mass will be a strong indication for two families of compact stars. (abridged)

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thEPJA(2016)·162 citations
26. 26*

    Search for Nucleon and Dinucleon Decays with an Invisible Particle and a Charged Lepton in the Final State at the Super-Kamiokande Experiment

    V. Takhistov🇺🇸 · K. Abe🇯🇵 · Y. Haga🇯🇵 · Y. Hayato🇯🇵 · M. Ikeda🇯🇵 · K. Iyogi🇯🇵 · J. Kameda🇯🇵 · Y. Kishimoto🇯🇵 · M. Miura🇯🇵 · S. Moriyama🇯🇵 · M. Nakahata🇯🇵 · T. Nakajima🇯🇵 and 116 other authors

    Search results for nucleon decays $p\to e^{+}X$, $p\to {\mu }^{+}X$, $n\to \nu \gamma$ (where $X$ is an invisible, massless particle) as well as dinucleon decays $np\to e^{+}\nu$, $np\to {\mu }^{+}\nu$ and $np\to {\tau }^{+}\nu$ in the Super-Kamiokande experiment are presented. Using single-ring data from an exposure of 273.4 kton $\cdot$ years, a search for these decays yields a result consistent with no signal. Accordingly, lower limits on the partial lifetimes of ${\tau }_{p\to e^{+}X}>7.9\times 10^{32}$ years, ${\tau }_{p\to {\mu }^{+}X}>4.1\times 10^{32}$ years, ${\tau }_{n\to \nu \gamma }>5.5\times 10^{32}$ years, ${\tau }_{np\to e^{+}\nu }>2.6\times 10^{32}$ years, ${\tau }_{np\to {\mu }^{+}\nu }>2.2\times 10^{32}$ years and ${\tau }_{np\to {\tau }^{+}\nu }>2.9\times 10^{31}$ years at a $90\%$ confidence level are obtained. Some of these searches are novel.

    ↳ hep-exhep-phPRL(2015)·61 citations
27. 27*

    The sigma meson from lattice QCD with two-pion interpolating operators

    Dean Howarth🇺🇸 · Joel Giedt🇺🇸

    In this article we describe our studies of the sigma meson, f_0(500), using two-pion correlation functions. We use lattice quantum chromodynamics in the quenched approximation with so-called clover fermions. By working at unphysical pion masses we are able to identify a would-be resonance with mass less than $2m_{\pi }$, and then extrapolate to the physical point. We include the most important annihilation diagram, which is "partially disconnnected" or "single annihilation." Because this diagram is quite expensive to compute, we introduce a somewhat novel technique for the computation of all-to-all diagrams, based on momentum sources and a truncation in momentum space. In practice, we use only $\mathbf{p}=0$ modes, so the method reduces to wall sources. At the point where the mass of the pion takes its physical value, we find a resonance in the $0^{++}$ two-pion channel with a mass of approximately $609\pm 80$ MeV, consistent with the expected properties of the sigma meson, given the approximations we are making.

    ↳ hep-lathep-phnucl-thInt.J.Mod.Phys.C(2017)·14 citations
28. 28*

    A viscous blast-wave model for relativistic heavy-ion collisions

    Amaresh Jaiswal🇩🇪 · Volker Koch🇺🇸

    Using a viscosity-based survival scale for geometrical perturbations formed in the early stages of relativistic heavy-ion collisions, we model the radial flow velocity during freeze-out. Subsequently, we employ the Cooper-Frye freeze-out prescription, with first-order viscous corrections to the distribution function, to obtain the transverse momentum distribution of particle yields and flow harmonics. For initial eccentricities, we use the results of Monte Carlo Glauber model. We fix the blast-wave model parameters by fitting the transverse momentum spectra of identified particles at the Large Hadron Collider (LHC) and demonstrate that this leads to a fairly good agreement with transverse momentum distribution of elliptic and triangular flow for various centralities. Within this viscous blast-wave model, we estimate the shear viscosity to entropy density ratio $\eta /s\simeq 0.24$ at the LHC.

    ↳ nucl-thhep-ph25 citations
29. 29*

    Unitary Limit of Two-Nucleon Interactions in Strong Magnetic Fields

    William Detmold🇺🇸 · Kostas Orginos🇺🇸 · Assumpta Parreno🇪🇸 · Martin J. Savage🇺🇸 · Brian C. Tiburzi🇺🇸 · Silas R. Beane🇺🇸 · Emmanuel Chang🇺🇸

    Two-nucleon systems are shown to exhibit large scattering lengths in strong magnetic fields at unphysical quark masses, and the trends toward the physical values indicate that such features may exist in nature. Lattice QCD calculations of the energies of one and two nucleons systems are performed at pion masses of $m_{\pi }\sim 450$ and 806 MeV in uniform, time-independent magnetic fields of strength {\bf B}| \sim 10^{19}$-$10^{20}$ Gauss to determine the response of these hadronic systems to large magnetic fields. Fields of this strength may exist inside magnetars and in peripheral relativistic heavy ion collisions, and the unitary behavior at large scattering lengths may have important consequences for these systems.

    ↳ hep-lathep-phnucl-thPRL(2016)·32 citations
30. 30*

    Curvature Perturbation and Domain Wall Formation with Pseudo Scaling Scalar Dynamics

    Yohei Ema🇯🇵 · Kazunori Nakayama🇯🇵 · Masahiro Takimoto🇯🇵

    Cosmological dynamics of scalar field with a monomial potential ${\varphi }^n$ with a general background equation of state is revisited. It is known that if $n$ is smaller than a critical value, the scalar field exhibits a coherent oscillation and if $n$ is larger it obeys a scaling solution without oscillation. We study in detail the case where $n$ is equal to the critical value, and find a peculiar scalar dynamics which is neither oscillating nor scaling solution, and we call it a pseudo scaling solution. We also discuss cosmological implications of a pseudo scaling scalar dynamics, such as the curvature perturbation and the domain wall problem.

    ↳ gr-qcastro-ph.COhep-phJCAP(2016)·8 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.