arXiv subjects

Bin He

Publications and source records attributed to Bin He.

96 records · Page 6Linked to original sources

arXiv2012

Inverse Seesaw in NMSSM and 126 GeV Higgs Boson

We consider extensions of the next-to-minimal supersymmetric model (NMSSM) in which the observed neutrino masses are generated through a TeV scale inverse seesaw mechanism. The new particles associated with this mechanism can have sizable couplings to the Higgs field which can yield a large contribution to the mass of the lightest CP-even Higgs boson. With this new contribution, a 126 GeV Higgs is possible along with order of 200 GeV masses for the stop quarks for a broad range of \tanβ. The Higgs production and decay in the diphoton channel can be enhanced due to this new contribution. It is also possible to solve the little hierarchy problem in this model without invoking a maximal value for the NMSSM trilinear coupling and without severe restrictions on the value of \tanβ.

hep-ph↗

arXiv2012

Ultrafast pump-probe spectroscopic signatures of superconducting and pseudogap phases in YBa2Cu3O7-δ films

Femtosecond pump-probe spectroscopy is applied to identify transient optical signatures of phase transitions in optimally doped YBa2Cu3O7-δ films. To elucidate the dynamics of superconducting and pseudogap phases, the slow thermal component is removed from the time-domain traces of photo-induced reflectivity in a high-flux regime with low frequency pulse rate. The rescaled data exhibit distinct signatures of the phase separation with abrupt changes at the onsets of TSC and TPG in excellent agreement with transport data. Compared to the superconducting phase, the response of the pseudogap phase is characterized by the strongly reduced reflectivity change accompanied by a faster recovery time.

cond-mat.supr-con↗

arXiv2012

Impact of LHC Searches on NLSP Top Squark and Gluino Mass

We explore the implications of 7 TeV LHC searches for a scenario in which one of the stops is the next-to lightest supersymmetric particle (NLSP). The NLSP stop (\tilde{t}_1) is assumed to decay exclusively into neutralino and charm quark. We consider processes where the stops are pair produced together with a hard QCD jet. We also consider stop quarks from gluino decays, \tilde{g}\to t\tilde{t}_1^\ast+\bar{t}\tilde{t}_1. We show that the monojet ATLAS and CMS searches corresponding to 1 fb^{-1} of integrated luminosity are sensitive to stop masses of up to 160 GeV, with the 20% neutralino-stop coannihilation region essentially ruled out for M_{\tilde{t}_1}\lesssim 140 GeV. The region M_{\tilde{t}_1}\lesssim 130 GeV is excluded with even relatively larger mass difference, M_{\tilde{t}_1}-M_{\tildeχ_1^0}\sim 40 GeV, by the multi-jets search. The b-jet and same-sign dilepton searches are sensitive to a heavier gluino because they only pick up gluino pair production events followed by top quarks decaying into b-jets and same-sign dileptons, respectively. We find that the LHC data places a lower limit on the gluino mass in this scenario of about 600 GeV (700 GeV) from b-jets (same-sign dileptons) searches.

hep-ph↗

arXiv2012

125 GeV Higgs, Type III Seesaw and Gauge-Higgs Unification

Recently, both the ATLAS and CMS experiments have observed an excess of events that could be the first evidence for a 125 GeV Higgs boson. This is a few GeV below the (absolute) vacuum stability bound on the Higgs mass in the Standard Model (SM), assuming a Planck mass ultraviolet (UV) cutoff. In this paper, we study some implications of a 125 GeV Higgs boson for new physics in terms of the vacuum stability bound. We first consider the seesaw extension of the SM and find that in type III seesaw, the vacuum stability bound on the Higgs mass can be as low as 125 GeV for the seesaw scale around a TeV. Next we dicuss some alternative new physics models which provide an effective ultraviolet cutoff lower than the Planck mass. An effective cutoff Λ\simeq 10^{11} GeV leads to a vacuum stability bound on the Higgs mass of 125 GeV. In a gauge-Higgs unification scenario with five-dimensional flat spacetime, the so-called gauge-Higgs condition allows us to predict a Higgs mass of 125 GeV, with the compactification scale of the extra-dimension being identified as the cutoff scale Λ\simeq 10^{11} GeV. Identifying the compactification scale with the unification scale of the SM SU(2) gauge coupling and the top quark Yukawa coupling yields a Higgs mass of 121\pm 2 GeV.

hep-ph↗

arXiv2010

Higgs Boson Mass Bounds in Seesaw Extended Standard Model with Non-Minimal Gravitational Coupling

In the presence of non-minimal gravitational coupling $ ξH^\dagger H {\cal R}$ between the standard model (SM) Higgs doublet $H$ and the curvature scalar ${\cal R}$, the effective ultraviolet cutoff scale is given by $Λ_{\rm cut}\approx m_P/ξ$, where $m_P$ is the reduced Planck mass, and $ξ\gtrsim 1$ is a dimensionless coupling constant. In type I and type III seesaw extended SM, which can naturally explain the observed solar and atmospheric neutrino oscillations, we investigate the implications of this non-minimal gravitational coupling for the SM Higgs boson mass bounds based on vacuum stability and perturbativity arguments. A lower bound on the Higgs boson mass close to 120 GeV is realized with type III seesaw and $ξ\sim 10-10^3$.

hep-ph↗

arXiv2010

New Fermions at the LHC and Mass of the Higgs Boson

Unification at M_{GUT}\sim 3\times 10^{16} GeV of the three Standard Model (SM) gauge couplings can be achieved by postulating the existence of a pair of vectorlike fermions carrying SM charges and masses of order 300 GeV -- 1 TeV. The presence of these fermions significantly modifies the vacuum stability and perturbativity bounds on the mass of the SM Higgs boson. The new vacuum stability bound in this extended SM is estimated to be 117 GeV, to be compared with the SM prediction of about 128 GeV. An upper bound of 190 GeV is obtained based on perturbativity arguments. The impact on these predictions of type I seesaw physics is also discussed. The discovery of a relatively `light' Higgs boson with mass \sim 117 GeV could signal the presence of new vectorlike fermions within reach of the LHC.

hep-ph↗