12332850
New Higgs signals from vector boson fusion in R-parity violating supersymmetry
We investigate signals of the lightest neutral Higgs in an R-parity violating supersymmetric model through the vector boson fusion mechanism. Assuming that R-parity is violated through lepton number, and locating regions in the parameter space where decays of such a neutral scalar into a pair of lightest neutralinos can be significant, we proceed to calculate the event rates for final states arising from decays of the neutralinos through both $\lambda$-and $\lambda'$-type interactions. Regions of the parameter space where each of these types of interactions can lead to detectable events are identified. The possibilities where such signals can be faked by other superparticles (squarks, gluinos, charginos and neutralinos) are also investigated. It is found that over a sizable region, one can obtain distinguishable signals of an intermediate mass neutral scalar from a study of the suggested final states at the Large Hadron Collider.
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.
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.
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.
117242003
Azimuthal $B \to D^{*} \tau^{-} \bar{\nu_\tau}$ angular distribution with tensor operators
In a recent paper we performed a comprehensive study of the impact of new-physics operators with different Lorentz structures on $\BDstarellnu$ decays, $\ell = e^-, \mu^-, \tau^- $, involving the $b \to c l \nu_\ell$ transition. In this work we extend the previous calculation by including tensor operators. In the case of $\BDstartaunu $, we present the full three angle and $q^2$ angular distribution with tensor new physics operators with complex couplings. The impact of the tensor operators on various observables in the angular distribution, specially the azimuthal observables including the CP violating triple product asymmetries are discussed. It is shown that these azimuthal observables are very useful in discriminating different new physics operators. Finally we consider new physics leptoquark models with tensor interactions and show how the presence of additional scalar operators modify the predictions of the tensor operators.
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.
14477103
Charmless B decays to final states with radially excited vector mesons
Abstract We consider the weak decays of a B meson to final states that contain a S-wave radially excited vector meson. We consider vector–pseudoscalar final states and calculate ratios of the type B → ρ ′ π / B → ρπ , B → ω ′ π / B → ωπ and B → ϕ ′ π / B → ϕπ where ρ ′, ω ′ and ϕ ′ are higher ρ , ω and ϕ S-wave radial excitations. We find such decays to have larger or similar branching ratios compared to decays where the final state ρ , ω and ϕ are in the ground state. We also study the effect of radial mixing in the vector system generated from hyperfine interaction and the annihilation term.
17067570
Methods for measuring new-physics parameters in B decays
Recently, it was argued that new-physics (NP) effects in $B$ decays can be approximately parametrized in terms of a few quantities. As a result, $CP$ violation in the $B$ system allows one not only to detect the presence of NP, but also to measure its parameters. This will allow a partial identification of the NP, before its production at high-energy colliders. In this paper, we examine three methods for measuring NP parameters. The first uses a technique involving both $\overline{b}\ensuremath{\rightarrow}\overline{s}$ and $\overline{b}\ensuremath{\rightarrow}\overline{d}$ penguin $B$ decays. Depending on which pair of decays is used, the theoretical error is in the range $5\char21{}15%$. The second involves a comparison of $B\ensuremath{\rightarrow}\ensuremath{\pi}K$ and $B\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\pi}$ decays. Although the theoretical error is large ($\ensuremath{\gtrsim}25%$), the method can be performed now, with presently available data. The third is via a time-dependent angular analysis of $B\ensuremath{\rightarrow}{V}_{1}{V}_{2}$ decays. In this case, there is no theoretical error, but the technique is experimentally challenging, and the method applies only to those NP models whose weak phase is universal to all NP operators. A reliable identification of the NP will involve the measurement of the NP parameters in many different ways, and with as many $B$ decay modes as possible, so that it will be important to use all of these methods.
118496504
Model independent predictions for rare top decays with weak coupling
Measurements at B factories have provided important constraints on new physics in several rare processes involving the B meson. New physics, if present in the b quark sector may also affect the top sector. In an effective Lagrangian approach, we write down operators, where effects in the bottom and the top sector are related. Assuming the couplings of the operators to be of the same size as the weak coupling g of the standard model and taking into account constraints on new physics from the bottom sector as well as top branching ratios, we make predictions for the rare top decays t{yields}cV, where V={gamma}, Z. We find branching fractions for these decays within possible reach of the LHC. Predictions are also made for t{yields}sW.