Fri·Aug 21, 2015Friday·August 21, 2015

1. 01*

   Magnetized color superconducting cold quark matter within the SU(2)${}_f$ NJL model: a novel regularization scheme

   Pablo G. Allen🇦🇷 · Ana G. Grunfeld🇦🇷 · Norberto N. Scoccola🇦🇷

   The influence of intense magnetic fields on the behavior of color superconducting cold quark matter is investigated using an SU(2)${}_f$ NJL-type model for which a novel regulation scheme is introduced. In such a scheme the contributions which are explicitly dependent on the magnetic field turn out to be finite and, thus, do not require to be regularized. As a result of this, nonphysical oscillations that might arise in the alternative regularization schemes previously used in the literature are naturally removed. The sensitivity of our results to the model parametrization is analyzed.

   hep-phPRD(2015)·52 citations
2. 02*

   Electroweak vacuum stability and inflation via non-minimal derivative couplings to gravity

   Stefano Di Vita🇩🇪 · Cristiano Germani🇪🇸

   We show that the Standard Model vacuum can be stabilized if all particle propagators are non-minimally coupled to gravity. This is due to a Higgs-background dependent redefinition of the Standard Model fields: in terms of canonical variables and in the large Higgs field limit, the quantum fluctuations of the redefined fields are suppressed by the Higgs background. Thus, in this regime, quantum corrections to the tree-level electroweak potential are negligible. Finally, we show that in this framework the Higgs boson can be responsible for inflation. Due to a numerical coincidence that originates from the CMB data, inflation can happen if the Higgs boson mass, the top mass, and the QCD coupling lie in a region of the parameter space approximately equivalent than the one allowing for electroweak vacuum stability in the Standard Model. We find some (small) regions in the Standard Model parameter space in which the new interaction "rescues" the electroweak vacuum, which would not be stable in the Standard Model.

   hep-phastro-ph.COgr-qchep-thPRD(2016)·23 citations
3. 03*

   Aspects of High-Scale Supersymmetry in a Singlet-Extended Model

   Teppei Kitahara🇯🇵

   The nearly Minimal Supersymmetric Standard Model (nMSSM) is one of the promising models of the new physics, since this model can avoid hierarchy problem, mu problem, cosmological domain wall problem, and tadpole problem simultaneously. In this thesis, we consider the phenomenology of the nMSSM. Especially, we focus on the phenomenology of the dark matter and the baryon asymmetry in the universe generated by the electroweak baryogenesis mechanism. We find that with high-scale supersymmetry breaking the singlino can obtain a sizable radiative correction to the singlino mass, which opens a window for the singlet dark matter scenario with resonant annihilation via the exchange of the Higgs boson. We also propose a new electroweak baryogenesis scenario in the nMSSM with additional vector-like multiplets. If the soft supersymmetry breaking scale is O(10) TeV, these scenarios are compatible with each other and an observed mass of the Higgs boson, constraints by the electric dipole moments measurements and the flavor experiments. As a result of these two studies, we conclude that the nMSSM with a high-scale supersymmetry breaking is valid and can be probed by the direct direction of the singlino dark matter.

   hep-ph1 citation
4. 04*

   Gaugino mass in heavy sfermion scenario

   Keisuke Harigaya🇯🇵

   The heavy sfermion scenario is naturally realized when supersymmetry breaking fields are charged under some symmetry or are composite fields. There, scalar partners of standard model fermions and the gravitino are as heavy as O(10-1000) TeV while gauginos are as heavy as O(1) TeV. The scenario is not only consistent with the observed higgs mass, but also is free from cosmological problems such as the Polonyi problem and the gravitino problem. In the scenario, gauginos are primary targets of experimental searches. In this thesis, we discuss gaugino masses in the heavy sfermion scenario. First, we derive the so-called anomaly mediated gaugino mass in the superspace formalism of supergravity with a Wilsonian effective action. Then we calculate gaugino masses generated through other possible one-loop corrections by extra light matter fields and the QCD axion. Finally, we consider the case where some gauginos are degenerated in their masses with each other, because the thermal relic abundance of the lightest supersymmetric particle as well as the the strategy to search gauginos drastically change in this case. After calculating the thermal relic abundance of the lightest supersymmetric particle for the degenerated case, we discuss the phenomenology of gauginos at the Large Hadron Collider and cosmic ray experiments.

   hep-phhep-th1 citation
5. 05*

   Effective theory for neutral resonances and a statistical dissection of the ATLAS diboson excess

   Sylvain Fichet🇧🇷 · Gero von Gersdorff🇧🇷

   We classify the complete set of dimension-5 operators relevant for the resonant production of a singlet of spin 0 or 2 linearly coupled to the Standard Model (SM). We compute the decay width of such states as a function of the effective couplings, and provide the matching to various well-motivated New Physics scenarios. We then investigate the possibility that one of these neutral resonances be at the origin of the excess in diboson production recently reported by the ATLAS collaboration. We perform a shape analysis of the excess under full consideration of the systematic uncertainties to extract the width ${\Gamma }_{\mathrm{tot}}$ of the hypothetical resonance, finding it to be in the range 26 GeV $<{\Gamma }_{\mathrm{tot}}<$ 144 GeV at 95\% C.L. We then point out that the three overlapping selections $WW$, $WZ$, $ZZ$ reported by ATLAS follow a joint trivariate Poisson distribution, which opens the possibility of a thorough likelihood analysis of the event rates. The background systematic uncertainties are also included in our analysis. We show that the data do not require $WZ$ production and could thus in principle be explained by neutral resonances. We then use both the information on the width and the cross section, which prove to be highly complementary, to test the effective Lagrangians of singlet resonances. Regarding specific models, we find that neither scalars coupled via the Higgs-portal nor the Randall-Sundrum (RS) radion can explain the ATLAS anomaly. The RS graviton with all matter on the infrared (IR) brane can in principle fit the observed excess, while the RS model with matter propagating in the bulk requires the presence of IR brane kinetic terms for the gauge fields.

   hep-phJHEP(2015)·33 citations
6. 06*

   Prospects for Slepton Searches in Future Experiments

   Takahiro Yoshinaga🇯🇵

   Muon g-2 anomaly, which is mismatch between the theoretical and the experimental values of the anomalous magnetic moment of muons, provides a sensitive probe of new physics. In SUSY, if masses of the superpartners relevant to the muon g-2 are O(100) GeV, the SUSY contributions to the muon g-2 become sizable and the anomaly can be solved. There are two representative SUSY contributions to the muon g-2, the chargino and the neutralino contributions, respectively. Particularly, when the discrepancy of the muon g-2 is dominated by the neutralino contributions, it is found that the discrepancy can be explained if only the Bino and sleptons are light. This setup is "minimal" to solve the muon g-2 anomaly. In this dissertation, we discuss the "minimal" SUSY models where only the Bino and sleptons are light, while the other superparticles are decoupled. When the slepton soft masses are universal, we show that the upper bound on the smuon mass becomes 330 (460) GeV in order to solve the muon g-2 anomaly at the 1sigma (2 sigma) level. It is within the reach of LHC and ILC. Further, light staus might affect the Higgs coupling to di-photon, which is sensitive to new physics. We also study future prospects of the stau which contributes to the Higgs coupling. If the stau is heavier than the smuon, we show that the bound can be as large as 1.4 (1.9) TeV. Such non-universal slepton mass spectrum generically predicts too large LFV/CPV. We show that the models are expected to be probed by LHC/ILC and LFV/CPV complementarily in future.

   hep-ph0 citations
7. 07*

   Interplay between neutrino magnetic moments and $CP$ violating phases in left-right models

   D. Delepine🇲🇽 · H. Novales-Sánchez🇲🇽

   We revisit the neutrino magnetic moments (MMs) in the left-right model with non-manifest symmetry. After deriving an expression in terms of the Dirac and Majorana phases, we analyze the sensitivity of neutrino MMs to these $CP$-violating phases in two scenarios: 1) a maximal right mixing in which left- and right-handed neutrinos are mixed by the same matrix; and 2) a right-handed neutrino mixing whose off-diagonal entries are much smaller than the elements in the diagonal, but where the $CP$ phases remain general. Our results show that, even though certain values of the Majorana phases can eliminate neutrino MMs, the presence of a maximal $CP$-violating phase in neutrino mixing matrix, as favored by the discrepancy between T2K results and reactor measurements in neutrino oscillations, requires that at least one neutrino have a large nonzero MM.

   hep-phPRD(2015)·4 citations
8. 08*

   The Effects of Superhigh Magnetic Fields on Equations of States of Neutron Stars

   Z.F.Gao🇨🇳 · N.Wang🇨🇳 · Y.Xu🇺🇸 · H.Shan🇨🇳 · X.D.Li🇨🇳

   By introducing Dirac ?-function in superhigh magnetic field, we deduce a general formula for pressure of degenerate and relativistic electrons, Pe, which is suitable for superhigh magnetic fields, discuss the quantization of Landau levels of electrons, and consider the quantum electrodynamic(QED) effects on the equations of states (EOSs) for different matter systems. The main conclusions are as follows: the stronger the magnetic field strength, the higher the electron pressure becomes; compared with a common radio pulsar, a magnetar could be a more compact oblate spheroid-like deformed neutron star due to the anisotropic total pressure; and an increase in the maximum mass of a magnetar is expected because of the positive contribution of the magnetic field energy to the EOS of the star. Since this is an original work in which some uncertainties could exist, to further modify and perfect our theory model should be considered in our future studies.

   hep-phastro-ph.HEnucl-thAstron.Nachr.(2015)·18 citations
9. 09*

   The model that predicts the maximal 2-3 mixing and CP violation for neutrinos is revisited

   Eiichi Takasugi🇯🇵

   The model of the neutrino mass matrix which we proposed in 2000 is revisited in the light of the recent T2K experiments. This model has the special property that it predicts the maximal 2-3 mixing and CP violation under the some simple condition. In this model, if the condition is relaxed, the 2-3 angle and the CP violation deviate from their maximal values and they are related. We present such relations for typical cases.

   hep-phPTEP(2015)·0 citations
10. 10*

    Light-Front Quark Model Phenomenology Consistent with Chiral Symmetry

    Ho-Meoyng Choi🇰🇷 · Chueng-Ryong Ji🇺🇸

    We discuss the link between the chiral symmetry of QCD and the numerical results of the light-front quark model, analyzing both the twist-2 and twist-3 distribution amplitudes of a pion. In particular, we exhibit that the pion twist-3 distribution amplitude can flip the sign of curvature as the cutoff scale for the transverse momentum gets lower than a typical scale of around 1 GeV.

    hep-phEPJ Web Conf.(2016)·2 citations
11. 11*

    Seesaw mechanism at electron-electron colliders

    Takehiko Asaka🇯🇵 · Takanao Tsuyuki🇯🇵

    We consider the Standard Model with right-handed neutrinos to explain the masses of active neutrinos by the seesaw mechanism. Since active neutrinos as well as heavy neutral leptons are Majorana fermions in this case, the lepton number violating process can be induced. We discuss the inverse neutrinoless double beta decay $e^{-}{e}^{-}\to W^{-}{W}^{-}$ in the framework of the seesaw mechanism and its detectability at future colliders. It is shown that the cross section can be 17 fb for $\sqrt{s}=3$ TeV even with the stringent constraint from the neutrinoless double beta decays if three (or more) right-handed neutrinos exist. In such a case, the future $e^{-}{e}^{-}$ colliders can test lepton number violation mediated by a right-handed neutrino lighter than about 10 TeV.

    hep-phhep-exPRD(2015)·35 citations
12. 12*

    Implications of Unitarity and Charge Breaking Minima in Left-Right Symmetric Model

    Tanmoy Mondal🇮🇳 · Ujjal Kumar Dey🇮🇳 · Partha Konar🇮🇳

    We examine the usefulness of the unitarity conditions in Left-Right symmetric model which can translate into giving a stronger constraint on the model parameters together with the criteria derived from vacuum stability and perturbativity. In this light, we demonstrate the bounds on the masses of the physical scalars present in the model and find the scenario where multiple scalar modes are in the reach of Large Hadron Collider. We also analyse the additional conditions that can come from charge breaking minima in this context.

    hep-phPRD(2015)·8 citations
13. 13*

    Spin-2 Form Factors at Three Loop in QCD

    Taushif Ahmed🇮🇳 · Goutam Das🇮🇳 · Prakash Mathews🇮🇳 · Narayan Rana🇮🇳 · V. Ravindran🇮🇳

    Spin-2 fields are often candidates in physics beyond the Standard Model namely the models with extra-dimensions where spin-2 Kaluza-Klein gravitons couple to the fields of the SM. Also, in the context of Higgs searches, spin-2 fields have been studied as an alternative to the scalar Higgs boson. In this article, we present the complete three loop QCD radiative corrections to the spin-2 quark-antiquark and spin-2 gluon-gluon form factors in SU(N) gauge theory with $n_f$ light flavors. These form factors contribute to both quark-antiquark and gluon-gluon initiated processes involving spin-2 particle in the hadronic reactions at the LHC. We have studied the structure of infrared singularities in these form factors up to three loop level using Sudakov integro-differential equation and found that the anomalous dimensions originating from soft and collinear regions of the loop integrals coincide with those of the electroweak vector boson and Higgs form factors confirming the universality of the infrared singularities in QCD amplitudes.

    hep-phhep-exJHEP(2015)·23 citations
14. 14*

    Accretion of dark matter by stars

    Richard Brito🇵🇹 · Vitor Cardoso🇵🇹 · Hirotada Okawa🇯🇵

    Searches for dark matter imprints are one of the most active areas of current research. We focus here on light fields with mass $m_B$, such as axions and axion-like candidates. Using perturbative techniques and full-blown nonlinear Numerical Relativity methods, we show that (i) dark matter can pile up in the center of stars, leading to configurations and geometries oscillating with frequency which is a multiple of f=$2.510^{14}$ $m_B{c}^2$/eV Hz. These configurations are stable throughout most of the parameter space, and arise out of credible mechanisms for dark-matter capture. Stars with bosonic cores may also develop in other theories with effective mass couplings, such as (massless) scalar-tensor theories. We also show that (ii) collapse of the host star to a black hole is avoided by efficient gravitational cooling mechanisms.

    ↳ gr-qcastro-ph.COastro-ph.SRhep-ph+1PRL(2015)·106 citations
15. 15*

    Features and stability analysis of non-Schwarzschild black hole in quadratic gravity

    Yi-Fu Cai🇨🇳 · Hezi Zhang🇨🇳 · Junyu Liu🇨🇳 · Gong Cheng🇨🇳 · Min Wang🇨🇳

    Black holes are found to exist in gravitational theories with the presence of quadratic curvature terms and behave differently from the Schwarzschild solution. We present an exhaustive analysis for determining the quasinormal modes of a test scalar field propagating in a new class of black hole backgrounds in the case of pure Einstein-Weyl gravity. Our result shows that the field decay of quasinormal modes in such a non-Schwarzschild black hole behaves similarly to the Schwarzschild one, but the decay slope becomes much smoother due to the appearance of the Weyl tensor square in the background theory. We also analyze the frequencies of the quasinormal modes in order to characterize the properties of new back holes, and thus, if these modes can be the source of gravitational waves, the underlying theories may be testable in future gravitational wave experiments. We briefly comment on the issue of quantum (in)stability in this theory at linear order.

    ↳ hep-thgr-qchep-phJHEP(2016)·35 citations
16. 16*

    Hyperon Puzzle, Hadron-Quark Crossover and Massive Neutron Stars

    Kota Masuda🇯🇵 · Tetsuo Hatsuda🇯🇵 · Tatsuyuki Takatsuka🇯🇵

    Bulk properties of cold and hot neutron stars (NSs) are studied on the basis of the hadron-quark crossover picture where a smooth transition from the hadronic phase to the quark phase takes place at finite baryon density. By using a phenomenological equation of state (EOS) "CRover" which interpolates the two phases at around 3 times the nuclear matter density, it is found that the cold NSs with the gravitational mass larger than 2-solarmass can be sustained. This is in sharp contrast to the case of the first-order hadron-quark transition. The radii of the cold NSs with the CRover EOS are in the narrow range which is insensitive to the NS masses. Due to the stiffening of the EOS induced by the hadron-quark crossover, the central density of the NSs is at most 4 times the nuclear matter density and the hyperon-mixing barely occurs inside the NS core. This constitutes a solution of the long-standing hyperon puzzle. The effect of color superconductivity (CSC) on the NS structures is also examined with the hadron-quark crossover. For the typical strength of the diquark attraction, a slight softening of the EOS due to two-flavor CSC (2SC) takes place and the maximum mass is reduced by about 0.2-solarmass. The CRover EOS is generalized to the supernova matter at finite temperature to describe the hot NSs at birth. The hadron-quark crossover is found to decrease the central temperature of the hot NSs under isentropic condition. The gravitational energy release and the spin-up rate during the contraction from the hot NS to the cold NS are also estimated.

    ↳ nucl-thastro-ph.HEhep-phEPJA(2016)·66 citations
17. 17*

    Weak decay of Lambda_c^+ for the study of Lambda(1405) and Lambda(1670)

    Kenta Miyahara🇯🇵 · Tetsuo Hyodo🇯🇵 · Eulogio Oset🇪🇸

    We study the Lambda_c decay process to pi^+ and the meson-baryon final state for the analysis of Lambda resonances. Considering the Cabibbo-Kobayashi-Maskawa matrix, color suppression, diquark correlation and the kinematical condition, we show that the final meson-baryon state should be in a pure I=0 combination, when the meson-baryon invariant mass is small. Because the I=1 contamination usually makes it difficult to analyze Lambda resonances directly from experiments, the Lambda_c decay is an ideal process to study Lambda resonances. Calculating the final state interaction by chiral unitary approaches, we find that the piSigma invariant mass distributions have the same peak structure in the all charge combination of the piSigma states related to the higher pole of the two poles of the Lambda(1405). Furthermore, we obtain a clear the Lambda(1670) peak structure in the KbarN and etaLambda spectra.

    ↳ nucl-thhep-phPRC(2015)·72 citations
18. 18*

    Unidirectional Transport in Electronic and Photonic Weyl Materials by Dirac Mass Engineering

    Ren Bi🇨🇳 · Zhong Wang🇨🇳

    Unidirectional transports have been observed in two-dimensional systems, however, so far they have not been experimentally observed in three-dimensional bulk materials. In this theoretical work we show that the recently discovered Weyl materials provide a platform for unidirectional transports inside bulk materials. With high experimental feasibility, a complex Dirac mass can be generated and manipulated in the photonic Weyl crystals, creating unidirectionally propagating modes observable in transmission experiments. Possible realization in (electronic) Weyl semimetals is also studied. We show in a lattice model that, with a short-range interaction, the desired form of the Dirac mass can be spontaneously generated in a first-order transition.

    ↳ cond-mat.str-elcond-mat.mtrl-scihep-phhep-th+1PRB(2015)·11 citations
19. 19*

    Searching for Very High Energy Emission from Pulsars Using the High Altitude Water Cherenkov (HAWC) Observatory

    C. Alvarez Ochoa🇲🇽 · P. M. Saz Parkinson🇨🇳 · A. Belfiore🇮🇹 · A. Carramiñana🇲🇽 · C. Rivière🇺🇸 · E. Moreno Barbosa (for the HAWC collaboration)🇲🇽

    There are currently over 160 known gamma-ray pulsars. While most of them are detected only from space, at least two are now seen also from the ground. MAGIC and VERITAS have measured the gamma ray pulsed emission of the Crab pulsar up to hundreds of GeV and more recently MAGIC has reported emission at $\sim 2$ TeV. Furthermore, in the Southern Hemisphere, H.E.S.S. has detected the Vela pulsar above 30 GeV. In addition, non-pulsed TeV emission coincident with pulsars has been detected by many groups, including the Milagro Collaboration. These GeV-TeV observations open the possibility of searching for very-high-energy (VHE, > 100GeV) pulsations from gamma-rays pulsars in the HAWC field of view.

    ↳ astro-ph.HEastro-ph.IMhep-ph2 citations
20. 20*

    Neutron star structure from QCD

    Eduardo S. Fraga🇧🇷 · Aleksi Kurkela🇨🇭 · Aleksi Vuorinen🇫🇮

    In this review article, we argue that our current understanding of the thermodynamic properties of cold QCD matter, originating from first principles calculations at high and low densities, can be used to efficiently constrain the macroscopic properties of neutron stars. In particular, we demonstrate that combining state-of-the-art results from Chiral Effective Theory and perturbative QCD with the current bounds on neutron star masses, the Equation of State of neutron star matter can be obtained to an accuracy better than 30% at all densities.

    ↳ nucl-thastro-ph.HEhep-phEPJA(2016)·58 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.