118328469
Collider Signatures for Heavy Lepton Triplet in Type I+III Seesaw
The minimal SU(5) theory augmented by the fermionic adjoint representation restores the coupling constant unification and gives realistic neutrino masses and mixing through the hybrid Type I and Type III seesaw. The crucial prediction of the theory is an SU(2) lepton triplet with the mass below TeV. We study the signature of these heavy leptons and propose the strategy to test this mechanism at the hadron and lepton colliders. The smoking gun evidence of the theory is Delta L=2 lepton number violation through events of a pair of like-sign leptons plus four jets without significant missing energy at hadron colliders. We find that via this unique channel, the heavy lepton can be searched for up to a mass of 200 GeV at the Tevatron with 8 fb^-1, and up to 450 (700) GeV at the LHC of 14 TeV C.M.energy with 10 (100) fb^-1. The signal rate at the 10 TeV LHC is reduced to 60-35% for a mass of 200-700 GeV. We also comment on how to distinguish this theory from other models with similar heavy leptons. Finally, we compare the production rates and angular distributions of heavy leptons in e+e- collisions for various models.
15523033
Signatures of noncommutative QED at photon colliders
In this paper we study non-commutative (NC) QED signatures at photon colliders through pair production of charged leptons(l + l ) and charged scalars(H + H ). The NC corrections for the fermion pair production can be easily obtained since NC QED with fermions has been extensively studied in the literature. NC QED with scalars is less studied. To obtain the cross section for H + H productions, we first investigate the structure of NC QED with scalars, and then study the corrections due to the NC geometry to the ordinary QED cross sections. Finally by folding in the photon spectra for a γγ collider with laser back-scattered photons from the e + e machine, we obtain 95% CL lower bound on the NC scale using the above two processes. We find that, with √ s = 0.5, 1.0, and 1.5 TeV and integrated luminosity L = 500(fb 1 ), the NC scale up to 0.7, 1.2, and 1.6 TeV can be probed, respectively, while, for monochromatic photon beams, these numbers become 1.1, 1.7, 2.6 TeV, respectively.
15752198
Invisible decays of Higgs and other mesons in models with singlet neutrinos in large extra dimensions
Abstract In light of current atmospheric neutrino oscillation data, we revisit the invisible decay of the standard model Higgs boson and other pseudoscalar mesons which can be enhanced because of large number of KK modes in models with right-handed singlet neutrinos in large extra dimensions. We find that the invisible decay rate of Higgs can be as large as H→b b decay rate only for a very restricted region of parameter space. This parameter space is even further restricted if one demands that the dimensionless neutrino Yukawa coupling λ is O (1). We have also studied the scenarios where singlet neutrino propagate in a sub-space, which lowers the string scale M ∗ and keeps neutrino Yukawa coupling O (1). We have also considered decays of other spin-0 mesons to ν ν and found the rates to be too small for measurement.
6337992
Constraining anomaly mediated supersymmetry breaking framework via ongoing muon g − 2 experiment at Brookhaven
The ongoing high precision E821 Brookhaven National Laboratory experiment on muon $g\ensuremath{-}2$ is promising to probe a theory involving supersymmetry. We have studied the constraints on the minimal anomaly mediated supersymmetry breaking (AMSB) model using the current data of muon $g\ensuremath{-}2$ from Brookhaven. A scenario of seeing no deviation from the standard model is also considered, within a $2\ensuremath{\sigma}$ limit of the combined error from the standard model result and the Brookhaven predicted uncertainty level. The resulting constraint is found to be complementary to what one obtains from $\stackrel{\ensuremath{\rightarrow}}{b}s+\ensuremath{\gamma}$ bounds within the AMSB scenario, since only a definite sign of $\ensuremath{\mu}$ is effectively probed via $\stackrel{\ensuremath{\rightarrow}}{b}s+\ensuremath{\gamma}.$ A few relevant generic features of the model are also described for disallowed regions of parameter space.
119238804
Sneutrino-antisneutrino oscillation at the Tevatron
Sneutrino-antisneutrino oscillation can be a very useful probe to look for signatures of lepton number violation ({Delta}L=2) at the Tevatron. Here, we discuss a scenario where the total decay width of the sneutrino is very small, producing interesting signals at the Tevatron for a mass splitting {Delta}m as small as 10{sup -14} GeV between the sneutrino mass eigenstates.
17303620
Study of single sneutrino production in association with fermion pairs at polarized photon colliders
We investigate single sneutrino production in the context of R-parity-violating supersymmetry at future ?? linear colliders. The sneutrino is produced in association with fermion pairs and it is shown that its decays into two further fermions will lead to a clean signal. We also discuss possible standard model backgrounds and the effects of beam polarization.
123551661
Entropy scaling in high-energy nucleus–nucleus interactions
We studied the multiparticle production in high-energy nucleus–nucleus interactions in terms of particle entropy in 16O–AgBr and 32S–AgBr interactions at 60 A GeV and 200 A GeV, respectively. An approximate scaling behavior of total produced entropy normalized to maximum rapidity in the center of mass frame measured in different rapidity bins has been reported. The scaling behavior is not supported either by the FRITIOF model or by the Monte Carlo simulated events.
115390730
MAXIMUM PSEUDORAPIDITY GAP ANALYSIS IN NUCLEAR INTERACTIONS FROM A FEW GeV TO FEW HUNDRED GeV
This paper presents new results on the maximum gap (∆max) in the pseudorapidity distribution of charged particles in individual events in Mg-AgBr, O-AgBr and S-AgBr interaction in the energy range 4.5− 200 AGeV. The location of the ∆max in an event and the experimental ∆max distribution at all energies has been studied in details. It has been observed that Gaussian distribution can describe the experimental data satisfactorily over the entire energy range.
120393441
Chaos analysis of nuclear fragments in high energy collisions
This paper deals with fixed target AGS and SPS data of beam energies 14.5 and 200 A GeV respectively. A detailed study on chaos in the nuclear fragmentation process of 28Si–AgBr interactions at 14.5 A GeV and 32S–AgBr interactions at 200 A GeV has been performed using a new parameter, the entropy index. The analysis provides new data on the evidence of the erratic behavior of the target fragments signifying chaotic target fragmentation and also quantify the measure for chaos in high and ultra-high energy heavy-ion interactions. Further, it is also observed that the target fragmentation process becomes less chaotic with the increase of average multiplicities of the final states.
122688628
Multifractal detrended fluctuation analysis of pseudorapidity and azimuthal distribution of pions emitted in high energy nuclear collisions
In this paper multifractal analysis of fluctuation pattern of pions emitted in 32S-AgBr and 16O-AgBr interactions at 200 GeV and 60 GeV, respectively, is performed in the framework of multifractal detrended fluctuation analysis (MFDFA). The pseudorapidity and azimuthal distributions exhibit multifractal scaling properties at both energies. The variation of multifractal width with energy is also studied. The study reveals a dependence of multifractal width on energy in pseudorapidity space while no such dependence is observed in azimuthal space.
115461364
FLUCTUATION OF PIONS IN RELATIVISTIC AND ULTRARELATIVISTIC NUCLEAR COLLISIONS - SCALE DEPENDENT OR NOT?
Fluctuation pattern of pions is investigated in a wide range of projectile energy from 4.5 AGeV ( 24 Mg-AgBr interactions) to 200 AGeV ( 32 S-AgBr interactions). Two-dimensional analysis is performed. To obtain the correct phase-space partition condition considering anisotropy of phase space, we use the concept of Hurst exponent H. The analysis is performed in a rigorous way by fitting one-dimensional factorial moment saturation curves. The effective fluctuation strength αeff is calculated. The study reveals that the fluctuation pattern is scale-dependent at both relativistic and ultrarelativistic energies.