122486006
NLO QCD corrections to drell-yan in TeV-scale gravity models
In TeV scale gravity models, we present the NLO-QCD corrections for the double differential cross sections in the scattering angle for dilepton production at hadron colliders. The quantitative impact of QCD corrections for extra dimension searches at LHC and Tevatron are investigated for both ADD and RS models through K-factors. We also show how the inclusion of QCD corrections to NLO stabilises the cross section with respect to renormalisation and factorisation scale variations.
15386012
Searching for signals of minimal length in extra dimensional models using dilepton production at hadron colliders
Theories of quantum gravity suggest the existence of a minimal length scale. It is interesting to speculate what the consequences of the existence of such a length scale would be for models of large extra dimensions, in particular, the ADD model. When ADD model is conflated with the minimal length scale scenario, processes involving virtual exchange of gravitons cease to be ulraviolet divergent. We study the production of dileptons at hadron colliders as an example of a process mediated by virtual gravitons. We find that the bounds we derive on the effective string scale are significantly different (in fact, less stringent) from those derived in the conventional ADD model, both at the upgraded Tevatron and the large hadron collider.
121827797
Finite tension strings in SU(2) gauge theory
Abstract The second-order field equations of the SU(2) Higgs model are studied and a new class of string solutions is obtained. The tension is finite and scale-dependent and the strings are of minus one unit flux.
119270253
NNLO QCD corrections to the resonant sneutrino/slepton production at hadron colliders
We present a complete next to next to leading order QCD corrections to the resonant sneutrino and charged slepton production cross sections at hadronic colliders such as the Tevatron and the Large Hadron Collider within the context of R-parity violating supersymmetric model. We have demonstrated the role of these corrections in reducing uncertainties resulting from renormalisation and factorisation scales and thereby making our predictions reliable. We have incorporated soft gluon effects at N 3 LO level in order to study the stability of our results under perturbation. The NNLO corrections are found to be large and significant. The results obtained in this article are also applicable to resonance production of any color-neutral scalar.
121522381
GLUONIC CONTRIBUTIONS TO SPIN-DEPENDENT WEAK STRUCTURE FUNCTIONS: METHOD OF FACTORIZATION
We compute the gluonic contributions to the spin-dependent weak structure functions (i=1, 3, 4), using the factorization theorem in the minimal subtraction scheme, . We have considered the most general case where the quark flavor masses are distinguished and the gluons are off mass shell. The gluonic contribution to the first moment of is found to vanish and do not receive leading order gluonic contribution. These results are shown to be free of mass singularities.
9952561
Testing TeV scale quantum gravity using Dijet production at the Tevatron
Dijet production at the Tevatron including effects of virtual exchanges of spin-2 Kaluza-Klein modes in theories with large extra dimensions is considered. The experimental dijet mass and angular distribution are exploited to obtain stringent limits ( > 1.2 TeV) on the effective string scale MS.
122212810
Carruthers’ theorem for any spin and parastatistics
SummaryIt is shown that Carruthers’ theorem (that particle multiplets of half-integral isospin cannot be self-conjugate) holds even for particles which obey the general parastatistics instead of the usual Bose or Fermi statistics.RiassuntoSi dimostra che il teorema di Carruther (sull’impossibilità di autoconiugazione per multipletti di particelle con isospin semintero) value anche per particelle che obbediscono solo alla parastatistica generale invece che alla statistica consueta di Bose o Fermi.
120046449
Evaluation of the density matrix for an ensemble of anharmonic oscillators by a path integral approach
Considering the Feynman path integral representation for the configuration-space density matrix for an ensemble of anharmonic oscillators, we determine the ‘stationary paths’ near which the integrand remains stationary. By taking the path integral to be saturated by contributions from the neighborhood of the path which maximizes the integrand we evaluate the density matrix explicitly in analytic form. This seems to be the first such evaluation of a path integral for a system not describable by a quadratic Hamiltonian. We also comment briefly on the question of analyticity with respect to the perturbation parameter.
120479737
Arbitrary‐Spin Wave Equations and Lorentz Invariance
In an earlier paper it was shown that invariance of the arbitrary‐spin wave equation i(∂ψ/∂t) = Hψ [with ψ transforming according to the representation D(0,s)⊕D(s,0) under rotations, T, C, and P, and boosts in the direction of the momentum, permits four infinite classes of solutions for H. Here we show that when invariance under boosts transverse to the momentum also is imposed, just two possible forms for H survive (in the c‐number formalism). When we go over to the q‐number theory, one of these forms leads to a consistent theory for half‐integer spins only and the other for integer spins.
121298874
Dynamics of a nonlinear field
Abstract A systematic study is made of the plane wave modes of a nonlinear c -number field ( λφ 4 model) and interesting features of the behavior of such fields, which do not seem to have been observed before, are brought out. These relate to the case λ lower bound on the energy density in the wave field. The case of fields with higher nonlinearities is briefly considered.
120658454
Consistency of spin-1 theories in external electromagnetic fields
It is known that while spin-1 (Proca) theory with minimal electromagnetic interaction is marred by the Corben-Schwinger anomaly, the inclusion of specific types of 'anomalous' interactions lead to other difficulties such as non-causality of propagation, and the energy spectrum (in homogeneous magnetic fields of sufficient strength) becoming partially non-real. The authors investigate whether, by making the anomalous terms (introduced into the Duffin-Kemmer-Petiau equation) sufficiently general, it is possible to escape these inconsistencies. The answer, unfortunately, turns out to be in the negative. They comment briefly on other formulations for spin-1.