Can Polarised Drell-Yan Shed More Light On The Proton Spin?

We analyse polarised Drell-Yan process using the factorisation method and derive operator definitions for polarised parton distribution functions. We demonstrate that a factorisation analogous to that in the unpolarised Drell-Yan case holds in this process. We study the leading order gluonic contribution to the first moment of polarised Drell-Yan function and show that it is consistent with results obtained from polarised deep inelastic scattering.Comment: 12 page

Neutral Triple Vector Boson Production in Randall-Sundrum Model at the LHC

In this paper, triple neutral electroweak gauge boson production processes, viz. \gamma\gamma\gamma, \gamma\gamma Z, \gamma ZZ and ZZZ productions merged to 1-jet have been studied at the leading order in QCD in the context of Randall-Sundrum model at the LHC with center of mass energy \sqrt{S}=13 TeV. Decay of Z bosons into lepton-pairs has been considered. We present a selection of kinematical distributions matched to parton shower and show their deviation from the SM results as a result of the RS model. The uncertainties as a result of the factorization and renormalization scales are also presented.Comment: 18 pages, 7 figures, version to appear in PR

Polarised and Unpolarised Charmonium Production at Higher Orders in v

We study the unpolarised and polarised hadro-production of charmonium in non-relativistic QCD (NRQCD) at low transverse momentum, including sufficiently higher orders in the relative velocity, $v$, so as to study the ratio of $\chi_{c1}$ and $\chi_{c2}$ production rates.Comment: 4 pages, 1 Postscript figure, LaTeX, Presented at the QCD97 Euroconference, Montpellier, July 3-9, 1997, to appear in Nuclear Physics B Proceedings Supplemen

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 ($\sim 1.2$ TeV) on the effective string scale $M_S$.Comment: Minor changes in the text and references updated, 8 pages, LaTeX, 1 ps figur

RS resonance in di-final state production at the LHC to NLO+PS accuracy

We study the di-final state processes ($\ell^+ \ell^-$, $\gamma \gamma$, $ZZ$, $W^+ W^-$) to NLO+PS accuracy, as a result of both the SM and RS Kaluza-Klein graviton excitations. Decay of the electroweak gauge boson final states to different leptonic states are included at the showering stage. A selection of the results has been presented with PDF and scale uncertainties for various distributions. Using the di-lepton and di-photon final states, we present the search sensitivity, for the $14$ TeV LHC at $50$ fb$^{-1}$ luminosity.Comment: 20 pages, 14 figure

eta_c Production at the Tevatron: A test of NRQCD

We use NRQCD to predict the cross section for $\eta_c$ production at the Tevatron. The non-perturbative matrix elements required are obtained, using heavy-quark symmetry, from the matrix elements determined from the CDF $J/\psi$ data. Our numbers are, therefore, predictions of NRQCD and provide a very good test of it. Even after taking into account the small branching ratio of the $\eta_c$ into two photons, a substantial rate for the production of this resonance at the Tevatron is expected.Comment: 6 pages, LaTeX, 1 ps figure, Revised version to appear in Physics Letters

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 $N^3LO$ 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.Comment: 45 pages, 17 figure

Two-Loop QCD Corrections to Higgs →b+bˉ+g\rightarrow b + \bar{b} + g Amplitude

Exclusive observables involving Higgs boson in association with jets are often well suited to study the Higgs boson properties. They are rates involving cuts on the final state jets or differential distributions of rapidity, transverse momentum of the observed Higgs boson. While they get dominant contributions from gluon initiated partonic subprocesses, it is important to include the subdominant ones coming from other channels. In this article, we study one such channel namely the Higgs production in association with a jet in bottom anti-bottom annihilation process. We compute relevant amplitude $H\rightarrow b+\overline b+g$ up to two loop level in QCD where Higgs couples to bottom quark through Yukawa coupling. We use projection operators to obtain the coefficients for each tensorial structure appearing in this process. We have demonstrated that the renormalized amplitudes do have the right infrared structure predicted by the QCD factorization in dimensional regularization. The finite parts of the one and two loop amplitudes are presented after subtracting the infrared poles using Catani's subtraction operators.Comment: Published version; 25 pages, 2 figures; v2: analytically continued result added, typos are correcte

Angular distribution of Drell-Yan process at hadron colliders to NLO-QCD in models of TeV scale gravity

In TeV scale gravity models, for dilepton production at hadron colliders, we present the NLO-QCD corrections for the double differential cross section in the invariant mass and scattering angle. For both ADD and RS models, the quantitative impact of QCD corrections for extra dimension searches at LHC and Tevatron are investigated. We present the K-factors for both ADD and RS models at LHC and Tevatron. Inclusion of QCD corrections to NLO stabilises the cross section with respect to scale variations.Comment: 35 pages, 12 figures, version to appear in NP