Subjects: Geosciences >> Space Physics submitted time 2016-12-22
Abstract: We study a holographic model with vector condensate by coupling the anti-de Sitter gravity to an Abelian gauge field and a charged vector field in (3 + 1) dimensional spacetime. In this model there exists a non-minimal coupling of the vector field to the gauge field. We find that there is a critical temperature below which the charged vector condenses via a second order phase transition. The DC conductivity becomes infinite and the AC conductivity develops a gap in the condensed phase. We study the effect of a background magnetic field on the system. It is found that the background magnetic field can induce the condensate of the vector field even in the case without chemical potential/charge density. In the case with non-vanishing charge density, the transition temperature raises with the applied magnetic field, and the condensate of the charged vector operator forms a vortex lattice structure in the spatial directions perpendicular to the magnetic field.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-12-22
Abstract: We continue to study the holographic p-wave superconductor model in the Einstein-Maxwell-complex vector field theory with a non-minimal coupling between the complex vector field and the Maxwell field. In this paper we work in the AdS soliton background which describes a conformal field theory in the confined phase and focus on the probe approximation. We find that an applied magnetic field can lead to the condensate of the vector field and the AdS soliton instability. As a result, a vortex lattice structure forms in the spatial directions perpendicular to the applied magnetic field. As a comparison, we also discuss the vector condensate in the Einstein-SU(2) Yang-Mills theory and find that in the setup of the present paper, the Einstein-Maxwell-complex vector field model is a generalization of the SU(2) model in the sense that the vector field has a general mass and gyromagnetic ratio.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-12-22
Abstract: We study competition between s-wave order and d-wave order through two holographic superconductor models. We find that once the coexisting phase appears, it is always thermodynamically favored, and that the coexistence phase is narrow and one condensate tends to kill the other. The phase diagram is constructed for each model in terms of temperature and the ratio of charges of two orders. We further compare the behaviors of some thermodynamic quantities, and discuss the different aspects and identical ones between two models.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-12-22
Abstract: In a recent paper, arXiv:1309.4877, a holographic p-wave model has been proposed in an Einstein Maxwell-complex vector field theory with a negative cosmological constant. The model exhibits rich phase structure depending on the mass and the charge of the vector field. We investigate the behavior of the entanglement entropy of dual field theory in this model. When the above two model parameters change, we observe the second order, first order and zeroth order phase transitions from the behavior of the entanglement entropy at some intermediate temperatures. These imply that the entanglement entropy can indicate not only the occurrence of the phase transition, but also the order of the phase transition. The entanglement entropy is indeed a good probe to phase transition. Furthermore, the "retrograde condensation" which is a sub-dominated phase is also reflected on the entanglement entropy. (C) 2015 The Authors. Published by Elsevier B.V.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-28
Abstract: After the discovery of a standard model (SM)-like Higgs boson, naturalness strongly favors the next-to-minimal supersymmetric SM. In this letter, we point out that the natural next-to-minimal supersymmetric SM usually predicts the following CP-even Higgs H-i sector: (A) H-2 is the SM-like Higgs boson with mass pushed upward by a lighter H-1 with mass overwhelmingly within [m(H2)/2, m(H2)]; (B) m(H3) similar or equal to 2 mu/sin 2 beta greater than or similar to 300 GeV; (C) H-3 has a significant coupling to the top quark and can decay to H1H2 with a large branching ratio. Using a jet substructure we show that these three Higgs bosons can be discovered via gg -> H-3 -> H1H2 -> b (b) over barl nu jj at the 14 TeV LHC. In particular, the LEP-LHC scenario with H-1 similar or equal to 98 GeV has a very good discovery potential.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-28
Abstract: We observe a generic connection between LHC Higgs data and electroweak baryogenesis: the particle that contributes to the CP-odd hgg or h gamma gamma vertex would provide the CP-violating source during a first-order phase transition. It is illustrated in the two Higgs doublet model that a common complex phase controls the lightest Higgs properties at the LHC, electric dipole moments, and the CP-violating source for electroweak baryogenesis. We perform a general parametrization of Higgs effective couplings and a global fit to the LHC Higgs data. Current LHC measurements prefer a nonzero phase for tan beta less than or similar to 1 and electric dipole moment constraints still allow an order-one phase for tan beta similar to 1, which gives sufficient room to generate the correct cosmic baryon asymmetry. We also give some prospects in the direct measurements of CP violation in the Higgs sector at the LHC.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-27
Abstract: We analyze the observational potential of single t' production in both the t' -> bW and t' -> th decay channels at 8 TeV LHC using an integrated luminosity of 25 fb(-1). Our analysis is based on a simplified model with minimal coset SO(5)/SO(4) in which the t' is a singlet of the unbroken SO(4). The single t' production, as a consequence of electroweak symmetry breaking, is less kinematically suppressed, associated with a light forward jet and has boosted decay products at the 8 TeV LHC. Therefore it provides the most promising channel in searching for a heavy t'. We have exploited the above kinematical features and used the jet substructure method to reconstruct the boosted Higgs in th decay channel. It is shown that a strong constraint on the t'bW coupling (g(t'bW)/g(tbW,SM) < 0.2 similar to 0.3) at the 95% C. L. can be obtained for m(t') subset of (700, 1000) GeV.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-27
Abstract: We perform a detailed semianalytical analysis of the electroweak phase transition (EWPT) property in the Next-to-Minimal Supersymmetric standard model, which serves as a good benchmark model in which the 126 GeV Higgs mixes with a singlet. In this case, a strongly first-order electroweak phase transition (SFOEWPT) is achieved by the tree-level effects, and the phase transition strength gamma(c) is determined by the vacua energy gap at T = 0. We make an anatomy of the energy gap at both tree level and loop level and extract out a dimensionless phase transition parameter R-kappa equivalent to 4 kappa v(s)/A(kappa), which can replace A(kappa) in the parameterization and affect the light CP-odd/even Higgs spectra. We find that SFOEWPT only occurs in R-kappa similar to -1 and positive R-kappa less than or similar to O(10), which in the non-PQ limit case would prefer either a relatively light CP-odd or CP-even Higgs boson similar to(60, 100) GeV, and therefore serves as a smoking gun signal and requires new search strategies at the LHC.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-27
Abstract: With the assistance of two extra groups, i.e., an extra hidden gauge group SU(2)(D) and a global U(1) group, we propose a two component dark matter (DM) model. After the symmetry SU(2)(D) x U(1) being broken, we obtain both the vector and scalar DM candidates. The two DM candidates communicate with the standard model (SM) via three Higgs as multi-Higgs portals. The three Higgs are mixing states of the SM Higgs, the Higgs of the hidden sector and real part of a supplement complex scalar singlet. We study relic density and direct detection of DM in three scenarios. The resonance behaviors and interplay between the two component DM candidates are represented through investigating of the relic density in the parameter spaces of the two DMs masses. The electroweak precision parameters constrains the two Higgs portals couplings (lambda(m) and delta(2)). The relevant vacuum stability and naturalness problem in the parameter space of lambda(m) and delta(2) are studied as well. The model could alleviate these two problems in some parameter spaces under the constraints of electroweak precision observables and Higgs indirect search.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-24
Abstract: The gamma-ray excess observed by the Fermi-LAT in the Galactic Center can be interpreted by the dark matter annihilation to b (b) over bar via a light pseudoscalar in the next-to-minimal supersymmetric standard model (NMSSM). It is interesting to note that the corresponding singlet scalar is useful to achieve a strongly first-order phase transition required by the electroweak baryogenesis. In this paper, we investigate the possibility that the NMSSM model can simultaneously accommodate these two issues. The phase transition strength can be characterized by the vacua energy gap at zero temperature and be sufficiently enhanced by the tree-level effect in the NMSSM. We find that the annihilation of singlino/Higgsino dark matter (DM) particles occurring close to the light pseudoscalar resonance is favored by the Galactic Center excess and the observed DM relic density, and some resulting regions in the parameter space with a small kappa/lambda. and a negative A. can simultaneously account for a successful strongly first-order electroweak phase transition.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-24
Abstract: The W W production is the primary channel to directly probe the triple gauge couplings. We first analyze the e (+) e (-) -> W (+) W (-) process at the future lepton collider, China's proposed Circular Electron-Positron Collider (CEPC). We use the five kinematical angles in this process to constrain the anomalous triple gauge couplings and relevant dimension six operators at the CEPC up to the order of magnitude of 10(-4). The most sensible information is obtained from the distributions of the production scattering angle and the decay azimuthal angles. We also estimate constraints at the 14 TeV LHC, with both 300 fb(-1) and 3000 fb(-1) integrated luminosity from the leading lepton p (T) and azimuthal angle difference Delta I center dot (ll) distributions in the di-lepton channel. The constrain is somewhat weaker, up to the order of magnitude of 10(-3). The limits on the triple gauge couplings are complementary to those on the electroweak precision observables and Higgs couplings. Our results show that the gap between sensitivities of the electroweak and triple gauge boson precision can be significantly decreased to less than one order of magnitude at the 14 TeV LHC, and that both the two sensitivities can be further improved at the CEPC.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-24
Abstract: We present a new probe of strongly coupled electroweak symmetry breaking at the 14 TeV LHC by measuring a phase shift in the event distribution of the decay azimuthal angles in massive gauge boson scattering. One generically expects a large phase shift in the longitudinal gauge boson scattering amplitude due to the presence of broad resonances. This phase shift is observable as an interference effect between the strongly interacting longitudinal modes and the transverse modes of the gauge bosons. We find that even very broad resonances of masses up to 900 GeV can be probed at 3 sigma significance with a 3000 fb(-1) run of the LHC by using this technique. We also present the estimated reach for a future 50 TeV proton-proton collider.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-06-18
Abstract: With the assistance of a complex singlet, and an effective operator involving CP violations, the dark matter relic abundance and baryon asymmetry of the universe have been addressed simultaneously. We studied the electroweak baryogenesis mechanism systematically. The electroweak phase transition analysis indicates that the strong first order phase transition takes place by one-step or two-step type due to the dynamics of the energy gap between the electroweak vacuum and the vacuum of the complex singlet. The relation between the magnitude of baryon asymmetry of the universe and the phase transition type and strength has been explored in the framework of electroweak baryogenesis.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-14
Abstract: To obtain a standard model-like Higgs boson around 125 GeV in the minimal supersymmetric standard model with minimal gauge mediation of supersymmetry breaking (GMSB), a heavy stop at multi-TeV level is needed and incurs severe fine-tuning, which can be ameliorated in the framework of the deformed GMSB with visible-hidden direct Yukawa interactions (YGMSB). We examine some general features of the YGMSB and focus on the scenario with Higgs-messenger couplings (HYGMSB) which can automatically maintain the minimal flavor violation. It turns out that such a Yukawa mediation scenario can give a large -Lambda(t) and -m((t) over tildeL,R)(2), leading to a maximal stop mixing, and thus can readily give a light stop ((t) over tilde (1)) below the TeV scale. However, we find that in the minimal HYGMSB scenario, m(Hu)(2) is too large and then the electroweak symmetry breaking is inconsistent with the large stop mixing. To solve this problem, we modify the hidden sectors in two ways, adding a new strong gauge dynamics or introducing the (10, (10) over bar) messengers. For each case we present some numerical studies.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-09
Abstract: We continue to study the holographic p-wave superconductor model in the Einstein-Maxwell-complex vector field theory with a non-minimal coupling between the complex vector field and the Maxwell field. In this paper we work in the AdS soliton background which describes a conformal field theory in the confined phase and focus on the probe approximation. We find that an applied magnetic field can lead to the condensate of the vector field and the AdS soliton instability. As a result, a vortex lattice structure forms in the spatial directions perpendicular to the applied magnetic field. As a comparison, we also discuss the vector condensate in the Einstein-SU(2) Yang-Mills theory and find that in the setup of the present paper, the Einstein-Maxwell-complex vector field model is a generalization of the SU(2) model in the sense that the vector field has a general mass and gyromagnetic ratio.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-09
Abstract: We study a holographic p-wave superconductor model in a four dimensional Einstein-Maxwell-complex vector field theory with a negative cosmological constant. The complex vector field is charged under the Maxwell field. We solve the full coupled equations of motion of the system and find black hole solutions with the vector hair. The vector hairy black hole solutions are dual to a thermal state with the U(1) symmetry as well as the spatial rotational symmetry broken spontaneously. Depending on two parameters, the mass and charge of the vector field, we find a rich phase structure: zeroth order, first order and second order phase transitions can happen in this model. We also find "retrograde condensation" in which the hairy black hole solution exists only for the temperatures above a critical value with the free energy much larger than the one of the black hole without the vector hair. We construct the phase diagram for this system in terms of the temperature and charge of the vector field.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-09
Abstract: We study a holographic model with vector condensate by coupling the anti-de Sitter gravity to an Abelian gauge field and a charged vector field in (3 + 1) dimensional spacetime. In this model there exists a non-minimal coupling of the vector field to the gauge field. We find that there is a critical temperature below which the charged vector condenses via a second order phase transition. The DC conductivity becomes infinite and the AC conductivity develops a gap in the condensed phase. We study the effect of a background magnetic field on the system. It is found that the background magnetic field can induce the condensate of the vector field even in the case without chemical potential/charge density. In the case with non-vanishing charge density, the transition temperature raises with the applied magnetic field, and the condensate of the charged vector operator forms a vortex lattice structure in the spatial directions perpendicular to the magnetic field.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-09
Abstract: We construct a holographic multi-band superconductor model with each complex scalar field in the bulk minimally coupled to a same gauge field. Taking into account the back reaction of matter fields on the background geometry and focusing on the two band case with two scalar order parameters, we find that depending on the strength of the back reaction and the charge ratio of the two bulk scalars, five different superconducting phases exist, and three of five phases exhibit some region where both orders coexist and are thermodynamically favored. The other two superconducting phases have only one scalar order. The model exhibits rich phase structure and we construct the full diagram for the five superconducting phases. Our analysis indicates that the equivalent attractive interaction mediated by gravity between the two order parameters tends to make the coexistence of two orders much more easy rather than more difficult.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-09
Abstract: We continue our study of entanglement entropy in the holographic superconducting phase transitions. In this paper we consider the holographic p-wave superconductor/insulator model, where as the back reaction increases, the transition is changed from second order to first order. We find that unlike the s-wave case, there is no additional first order transition in the superconducting phase. We calculate the entanglement entropy for two strip geometries. One is parallel to the super current, and the other is orthogonal to the super current. In both cases, we find that the entanglement entropy monotonically increases with respect to the chemical potential.
Peer Review Status:Awaiting Review
Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-09
Abstract: Recently Lysov and Strominger [arXiv:1104.5502] showed that imposing Petrov type I condition on a (p+1)-dimensional time like hypersurface embedded in a (p+2)-dimensional vacuum Einstein gravity reduces the degrees of freedom in the extrinsic curvature of the hypersurface to that of a fluid on the hypersurface, and that the leading-order Einstein constraint equations in terms of the mean curvature of the embedding give the in compressible Navier-Stokes equations of the dual fluid. In this paper we show that the non-relativistic fluid dual to vacuum Einstein gravity does not satisfy the Petrov type I condition at next order, unless additional constraint such as their rotational condition is added. In addition, we show that this procedure can be inversed to derive the non-relativistic hydrodynamics with higher order corrections through imposing the Petrov type I condition, and that some second order transport coefficients can be extracted, but the dual "Petrov type I fluid" does not match the dual fluid constructed from the geometry of vacuum Einstein gravity in the non-relativistic limit. We discuss the procedure both on the finite cut off surface via the non-relativistic hydrodynamic expansion and on the highly accelerated surface via the near horizon expansion.
Peer Review Status:Awaiting Review