118715386
LHC limits on KK-parity non-conservation in the strong sector of universal extra-dimension models
Abstract In five-dimensional universal extra-dimensional models compactified on an S 1 / Z 2 orbifold four-dimensional kinetic terms are allowed at the two fixed points. If these terms are unequal then Kaluza–Klein (KK) parity is broken. Within such a framework we consider resonant production of the n = 1 KK-gluon at the LHC and its subsequent decay to t t ¯ , where both production and decay are KK-parity non-conserving. We use, for the first time, the exclusion data for a t t ¯ resonance obtained by the LHC experiments to limit the mass range of the lowest gluon excitation and, in a correlated fashion, of the n = 1 quark excitation of the KK-parity-violating model which are both found to be in the ballpark of 600–2000 GeV.
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.
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.
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.
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.
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.
15656176
Understanding the nature of Ds(2317) and Ds(2460) through nonleptonic B decays
We consider the nonleptonic B decays B→D(∗)Ds(2317) and B→D(∗)Ds(2460), involving the newly discovered Ds(2317) and the Ds(2460) states. We find that experiments indicate disagreement with model calculations of their properties and/or breakdown of the factorization assumption for these decays. We point out that decays involving Bs mesons where the Ds resonances can be produced via the weak decay of the b quark can provide further information about the nature of these newly discovered states. We also propose a model to calculate the two body nonleptonic decays B→D(∗)Ds(2317)(Ds(2460)), if the Ds(2317) and Ds(2460) are interpreted as DK and D∗K molecules.
118592122
Probing light pseudoscalar, axial vector states through $\eta_{b} \to\tau^{+}\tau^{-}$
In this paper, we explore the decay ${\ensuremath{\eta}}_{b}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ as a probe for a light pseudoscalar or a light axial vector state. We estimate the standard model branching ratio for this decay to be $\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}$. We show that considerably larger branching ratios, up to the present experimental limit of $\ensuremath{\sim}8%$, are possible in models with a light pseudoscalar or a light axial vector state. As we do not include possible mixing effects between the light pseudoscalar and the ${\ensuremath{\eta}}_{b}$, our results should be reliable when the pseudoscalar mass is away from the ${\ensuremath{\eta}}_{b}$ mass.
184760047
One 233 km Tunnel for Three Rings: e+e-, p anti-p, and mu+ mu-
119214554
A 233 km tunnel for lepton and hadron colliders
A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e+e−, pp, and μ+μ− collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e+e− colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e+e− collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp collider uses the high intensity Fermilab p source, exploits high cross sections for pp production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 6...