18756859
Hunting radions at linear colliders
Abstract We investigate the possibility to disentangle the radions in the Randall–Sundrum scenario from Higgs boson at the next generation high energy e + e − linear colliders. Due to trace anomaly, the radion coupling (and in turn the branching ratio) to gluons is enhanced over the same for the Standard Model (SM) higgs. We study the radion φ production at electron–positron colliders, via the process e + e − →ν ν φ , and propose to investigate radion decay to a pair of gluons. At 500 GeV center of mass energy, our signal is not very promising. We find our results are encouraging for finding radion and differentiating it from higgs for center of mass energies of 1 TeV and above.
119099061
Probing the violation of equivalence principle at a muon storage ring via neutrino oscillation
Abstract We examine the possible tests of violation of the gravitational equivalence principle (VEP) at a muon storage ring via neutrino oscillation experiments. If the gravitational interactions of the neutrinos are not diagonal in the flavour basis and the gravitational interaction eigenstates have different couplings to the gravitational field, this leads to the neutrino oscillation. If one starts with μ + beam then appearance of τ ± , e + and μ − in the final state are the signals for neutrino oscillation. We have estimated the number of μ − events in this scenario in ν μ – N deep inelastic scattering. Final state lepton energy distribution can be used to distinguish the VEP scenario from the others. A large area of VEP parameter space can be explored at a future muon storage ring facility with moderate beam energy.
118278744
Higgs Boson Signals in Three b-jet Final States at the Fermilab Tevatron
At the Fermilab Tevatron, final states with three tagged b-jets could play an important role in searches for a Higgs boson with mass in the range 100-300 GeV. These signals arise from gb fusion and we demonstrate their observability in the limit of a large b-quark Yukawa coupling. Rather promising discovery limits on such a coupling are obtained and consequent effects on the parameter space of the Higgs-boson sector in the MSSM are discussed.
54016829
Deciphering universal extra dimension from the top quark signals at the CERN LHC
Models based on Universal Extra Dimensions predict Kaluza-Klein (KK) excitations of all Standard Model (SM) particles. We examine the pair production of KK excitations of top- and bottom-quarks at the Large Hadron Collider. Once produced, the KK top/bottom quarks can decay to b-quarks, leptons and the lightest KK-particle, γ1, resulting in 2 b-jets, two opposite sign leptons and missing transverse momentum, thereby mimicing top-pair production. We show that, with a proper choice of kinematic cuts, an integrated luminosity of 100 fb−1 would allow a discovery for an inverse radius upto R−1 = 750GeV.
657627
Virtual graviton exchanges at the Z pole in large extra dimensions
Abstract In the framework of quantum gravity propagating in large extra dimensions, the effects of virtual Kaluza–Klein gravitons on the imaginary part of the amplitude of the process e + e − →f f are analyzed at the Z pole. Notably, the interference of the almost-continuous spectrum of the KK gravitons with the standard model resonant amplitude is finite and predictable in terms of the fundamental D-dimensional Planck scale MD. We find that, while the virtual-graviton effect on total cross sections vanishes at tree-level, both angular and polarization asymmetries are modified by terms whose relative effect is at most of order 10−4 for MD>1 TeV. Possible shifts in MZ, due to the changes in Breit–Wigner line shape are also discussed.
17475961
ZZH coupling: a probe to the origin of EWSB?
Abstract We argue that the ZZH coupling constitutes a simple probe of the nature of the scalar sector responsible for electroweak symmetry breaking. We demonstrate the efficacy of this measure through an analysis of four-dimensional models containing scalars in arbitrary representation of SU (2)× U (1), as well as extra-dimensional models with a non-factorizable geometry. A possible role for the t t H couplings is also discussed.
118381371
Searching for new physics with B-decay fake triple products
Abstract In pure-penguin b ¯ → s ¯ B → V 1 V 2 decays ( V 1 , 2 are vector mesons), f T / f L ≃ 1 has been observed ( f T ( f L ) is the polarization fraction of transverse (longitudinal) decays). Explanations of this unexpectedly large result have been given within the standard model (SM) and with new physics (NP). In this Letter, we show that these two explanations can be partially distinguished through the triple products (TPʼs) in these transitions. In particular, the SM predicts one of the two fake, CP-conserving TPʼs to be small ( | A T ( 2 ) | ⩽ 9 % ), while NP often gives larger values for | A T ( 2 ) | . We discuss the implications of the measurements of both fake TPʼs in B → ϕ K ⁎ – the present data prefer an SM explanation of f T / f L – and provide the SM predictions for B s 0 → ϕ ϕ .
118310374
Probing New Physics in Higgs Couplings to Fermions using an Angular Analysis
The standard-model Higgs boson couples to quarks through a parity-even scalar Hqcou- pling. We show that the rare Higgs decay H ! V Z, where V is a vector quarkonium state such as J/ψ (c¯) or �(1S) (bb), can be used to search for the presence of a parity-odd pseudoscalar Hq¯ q coupling. Since both V and Z can decay to a pair of charged leptons, this presents an experimentally-clean channel that can be observed at the high-luminosity LHC or a future hadron collider. The P-even and P-odd Hqcouplings can be measured by analyzing the angular distribution of the final-state leptons.
17090268
S-wave phase shift in Lambda-pi scattering
We calculate the s-wave strong interaction $\Lambda$$\pi$ phase shift at the $\Xi$ mass taking into account contributions from the ${{\frac{1}{2}}}^{-}$ and ${{\frac{3}{2}}}^{-}$ $\Sigma$ resonances. We find the S-wave phase shift to be small, of the order of 0.3 degrees and bounded by 0.5 degrees.
119257060
Higgs vacuum stability in the $B-L$ extended standard model
We study vacuum stability of B −L extension of the Standard Model (SM) and its supersymmetric version. We show that the generation of non-vanishing neutrino masses through TeV inverse seesaw mechanism leads to a cutoff scale of SM Higgs potential stability of order 10 5 GeV. However, in the non-supersymmetric B −L model, we find that the mixing between the SM-like Higgs and the B −L Higgs plays a crucial role in alleviating the vacuum stability problem. We also provide the constraints of stabilizing the Higgs potential in the supersymmetric B −L model.
118664901
Nonstandard interactions of tau neutrino via charged Higgs and $W'$ contribution
We consider charged Higgs and $W'$ gauge boson contributions to the quasielastic scattering $\nu_{\tau}+ n \rightarrow \tau^- + p$ and $\bar{\nu}_{\tau}+ p \rightarrow \tau^+ + n$ . These effects modify the standard model cross section for these processes and thus impact the extraction of the neutrino mixing angles $\theta_{23}$ and $\theta_{13}$ . We include form factor effects in our calculations and find the deviation of the actual mixing angle from the measured one, assuming the standard model cross section, can be significant and can depend on the energy of the neutrino.