8768919
NLO-QCD corrections to dilepton production in the Randall-Sundrum model
The dilepton production process at hadron colliders in the Randall-Sundrum (RS) model is studied at next-to-leading order in QCD. The NLO-QCD corrections have been computed for the virtual graviton exchange process in the RS model, in addition to the usual γ, Z-mediated processes of standard Drell-Yan. K-factors for the cross-sections at the LHC and Tevatron for differential in the invariant mass, Q, and the rapidity, Y, of the lepton pair are presented. We find the K-factors are large over substantial regions of the phase space.
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.
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.
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.
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.
123141603
Solution of the Fisk-Tait Equation for Spin 3/2 Particles in Interaction with a Homogeneous Magnetic Field
The Fisk--Tait wave equation for spin-3/2 particles, which has been shown to remain causal even with coupling to external fields, is shown to be also free of other types of difficulties by which the Rarita--Schwinger formalism is plagued. Unlike the latter, the Fisk----Tait equation with coupling to a homogeneous magnetic field has no modes with complex frequencies irrespective of the magnetic field strength. We show this by explicit solution of the equation. Further, the invariant scalar product in the Fisk-Tait theory, expressed in terms of the independent components of the wave function, is shown to be unaffected by the presence of the external field. (AIP)
118460186
A quantum-mechanically solvable nonpolynomial Lagrangian with velocity-dependent interaction
SummaryThe quantum-mechanical problem of the nonlinear oscillator with the Lagrangian L= 1/2 [x2-k0x2)/(l-λx2)] is solved exactly and the energy levels and eigenfunctions are obtained completely. This model (whenk0=0) is the zero-space-dimensional isoscalar analogue of the nonlinearSU2⊗ SU2 chirally invariant Lagrangian in the Gasiorowicz-Geffen co-ordinates and may also be considered as a modified version of the anharmonic-oscillator and Lee-Zumino models. The bound-state energy levels are found to have a linear dependence on the coupling parameter, in sharp contrast to the case of the familiar oscillator With quartic anharmonicity where the energy, as a function of λ, has complicated singularities at λ = 0. We investigate how far certain standard approximation procedures reproduce the exact results. The Bohr-Sommerfeld quantization procedure is found to reproduce the form of the boundstate energy levels correctly. Interestingly a perturbation-theoretic treatment also reproduces the correct results at least up to the order (λ2) to which we have carried our calculations.RiassuntoSi risolve esattamente il problema della meccanica quantistica dell’osoillatore non lineare con lagrangianoL = 1/2 [(x2-k0x2)/(l-λx2)] e se ne ottengono completamente le autofunzioni e i livelli energetici. Questo modello (quandok0 = 0) è l’analogo isoscalare con dimensione spaziale nulla del lagrangiano chiralmente invarianteSU2 ⊗ SU2 non lineare nelle coordinate di Gasiorowicz-Greffen e si può anche considerare come una versione modificata dei modelli dell’oscillatore anarmonico e di Lee-Zumino. Si trova che i livelli energetici di stato legato dipendono linearmente dal parametro di accoppiamento, in evidente contrasto con il caso familiare di oscillatore con anarmonicità del quart’ordine in cui l’energia, espressa in funzione di λ, presenta complicate singolarità per λ = 0. Si cerca di vedere sino a che punto certi procedimenti standard di approssimazione riproducono i risultati esatti. Si trova che il metodo di quantizzazione di Bohr-Sommerfeld riproduce correttamente la forma dei livelli di energia degli stati legati. È interessante che anche un trattamento con la teoria delle perturbazioni riproduca correttamente i risultati almeno fino all’ordine (λ2) al quale si sono spinti i calcoli.РезюмеТочно решается квант овомеханическая проблема нелинейног о осциллятора с Лагранжианом 

$$L = \frac{1}{2}\left[ {(x^2 - k_0 x^2 )/\left( {1 - \lambda x^2 } \right)} \right]$$

. Полу чены уровни энергии и собственные функции. Эта модель (когда k0=0) представляет изоска лярный аналог с нулевой пространст венной размерностью для нелинейногоSU2⊗SU2, ки рально инвариантного Лагра нжиана в координатах Газиоровича-Геффена и может рассматриват ься как модифицированны й вариант ангармонич еского осциллятора и моделей Ли-Зумино. Обн аружено, что энергети ческие уровни связанных сос тояний имеют линейную завис имость от параметра с вязи в противоположность с лучаю обычного осциллятор а с квадратичной ангармоничностью, дл я которого энергия, как функция Л, имеет си нгулярность при λ=0. Мы исследуем, насколько процедуры стандартных приближ ений воспроизводят т очные результаты. Получено, что процедура квантования Бора-Зом мерфельда правильно воспроизводит форму энергетических уровней свазанных со стояний. Интересно от метить, что в теории возмущений также получаются пра вильные результаты, п о крайней мере, до порядка (λ2), в ко тором мы производили наши в ычисления.
119912244
On the energy spectra of one-dimensional anharmonic oscillators
In this paper we present explicit and simple analytical formulae for the energy eigenvaluesEn (λ) of one-dimensional anharmonic oscillators characterized by the potentials 1/2mω2x2+λx2α withα=2, 3 and 4. A simple intuitive criterion supplemented by the requirement of correct asymptotic behaviour, has been employed in arriving at the formulae. Our energy values over a wide range ofn andλ are in good agreement with the numerical values computed by earlier workers through very elaborate techniques. To our knowledge this is the first time that formulae of such wide validity have been given. The results for pure power oscillators are trivially obtained by going over to theω→0 limit. Approximate analytic expressions for the low order even moments ofx are also given.
120399594
A simple accurate formula for the energy levels of oscillators with a quartic potential
Abstract In this note we present a simple analytical formula which reproduces the energy eigenvalues Ek(λ) of the pure quartic and quartic anharmonic oscillators with high accuracy for all values of the anharmonicity parameter λ and the level number k.
121160610
COVARIANT THEORY OF THE QUANTIZED ELECTROMAGNETIC FIELD WITH ONLY PHYSICAL PHOTONS.
A manifestly covariant procedure for quantization of the electro-magnetic potentials Amu is presented, wherein only two types of photons with space-like polarization vectors find a place. The non-appearance of unphysical photons corresponding to the longitudinal and scalar photons of other formulations is due to our insistence from the beginning that the Lorentz condition be satisfied (as an operator equation) by the Amu , and it makes the introduction of any indefinite metric unnecessary. The authors theory therefore leads to the same results in quantum electrodynamics as earlier formulations, but in a manifestly Lorentz covariant and gauge invariant fashion and without recourse to concepts like the indefinite metric or any other ad hoc prescriptions.