17034941
Invisible charginos and neutralinos from gauge boson fusion: a way to explore anomaly mediation.
We point out that vector boson fusion at the Large Hadron Collider (LHC) can lead to useful signals for charginos and neutralinos in supersymmetric scenarios where these particles are almost invisible. The proposed signals are just two forward jets with missing transverse energy. It is shown that, in this way, one can put by far the strongest constraint on the parameter space of a theory with anomaly mediated supersymmetry breaking at the LHC. In addition, scenarios where the lightest neutralinos and charginos are Higgsino-like can give signals of the above type.
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.
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.
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.
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.
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.
17027727
Getting SM and New Physics CP phases from $B$ Decays
A method to extract Standard Model(SM) CP phases involving B decays is presented. The method involves a pair of decays where one decay receives a significant $b \to d$ penguin contribution while the second has a significant $b \to s$ penguin contribution, but is dominated by a single amplitude. SM CP phase information is obtained using the fact that the $b \to s$ transition amplitude is related by SU(3) to a piece of the amplitude with the $b \to d$ transition. If there is significant new physics only in $b \to s$ transitions and not in $b \to d$ transitions then this method can be used to measure new physics(NP) phases.
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.
13923475
Measuring new physics parameters in B penguin decays
Abstract We examine new-physics (NP) effects in B decays with large b ¯ → s ¯ penguin amplitudes. Decays involving b ¯ → d ¯ penguins are assumed to be unaffected. We consider a model-independent parametrization of such NP. We argue that NP strong phases are negligible relative to those of the standard model. This allows us to describe the NP effects in terms of a small number of effective amplitudes A NP q ( q = u , d , s , c ) and corresponding weak phases Φ q . We then consider pairs of neutral B decays which are related by flavour SU(3) in the standard model. One receives a large b ¯ → s ¯ penguin component and has a NP contribution; the other has a b ¯ → d ¯ penguin amplitude and is unaffected by NP. The time-dependent measurement of these two decays allows the measurement of the NP parameters A NP q and  Φ q . The knowledge of these parameters allows us to rule out many NP models and thus partially identify the new physics.
119250962
STUDY OF CP VIOLATION IN $\Lambda_c^+$ DECAY
In this paper, we study CP violation in and decays, where B, P and V denote a light spin-½ baryon, pseudoscalar and a vector meson respectively. In these processes the T odd CP violating triple-product (TP) correlations are examined. The genuine CP violating observables which are composed of the helicity amplitudes occurring in the angular distribution are constructed. Experimentally, by performing a full angular analysis it is shown how one may extract the helicity amplitudes and then obtain the TP asymmetries. We estimate the TP asymmetries in decays to be negligible in the Standard Model making these processes an excellent place to look for new physics. Taking a two-Higgs doublet model, as an example of new physics, we show that large TP asymmetries are possible in these decays. Finally, we discuss how BES-III and super τ-charm experiments will be sensitive to these CP violating signals in decays.
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 .