10218302
Unparticle physics in diphoton production at the CERN LHC
We have considered the diphoton production in the unparticle physics at the LHC. The contributions of spin-0 and spin-2 unparticles to the diphoton production are studied in the invariant mass and other kinematical distributions, along with their dependencies on the model dependent parameters. It is found that the signal corresponding to the unparticles is significant for moderate values of the couplings.
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.
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.
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.
119919377
On mass zero indecomposable representations of the Poincaré group
Considering the space of massless‐particle wavefunctions transforming locally according to the irreducible representation D(m,n) of the homogeneous Lorentz group, we determine explicitly, by a direct and elementary method, the matrices constituting the (reducible but indecomposable) representation of Lorentz transformations with respect to a helicity basis.
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.
124211973
Stationary states of a spin-1 particle in a homogeneous magnetic field
We present a simple and complete determination of the energy spectrum and eigenfunctions of a relativistic spin-1 particle with arbitrary magnetic moment in a homogeneous magnetic field. The particle is described by a four-vector field satisfying the usual second-order equation including anomalous-magnetic-moment interaction. In the light of our results and those pertaining to the case when the external field is a Coulomb field, we discuss briefly the question of consistency of the vector theory at the basic c-number level.
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.
118914003
Wave equations for zero-mass particle with invariant helicities
SummaryWe present a brief discussion of the difficulties associated with taking the limitm→0 in massive-particle equations of the formi(∂ψ/∂t)=Hψ, in which ψ transforms according to theD(0,s)⊕D(s,0) representation of the homogeneous Lorentz group. It is pointed out that, though the HamiltonianH tends to a well-defined form asm→0, the resulting wave equation is still unsatisfactory as the invariant scalar product (in the space of solutions of the wave equation) has an unacceptable form. We observe that this difficulty is due to the indecomposability of the representation of the Poincaré group over wave functions transforming asD(0,s)⊕D(s,0) in the massless case. Making due allowance for this fact we obtain, in close parallel to the treatment for massive particles, wave equations for zero-mass particles with invariant helicities ±s. The relevant invariant scalar products are also determined.RiassuntoSi presenta una breve discussione associata con il limitem→0 in equazioni per particelle con massa della formai(∂ψ/∂t)=Hψ, in cuiψ si trasforma secondo la rappresentazioneD(0,s)⊕C(s,0) del gruppo di Lorentz omogeneo. Si mette in rilievo che, sebbene l’hamiltonianoH tenda ad una forma ben definita quandom→0, l’equazione d’onda risultante non è ancora soddisfacente in quanto il prodotto scalare invariante (nello spazio delle soluzioni dell’equazione d’onda) ha una forma inaccettabile. Si osserva che questa difficoltà è dovuta alla indecomponibilità della rappresentazione del gruppo di Poincaré rispetto alle funzioni d’onda che si trasformano comeD(0,s)⊕D(s, 0) nel caso senza massa. Tenendo dovuto conto di questo fatto si ottengono, in stretta analogia con il trattamento per particelle con massa, equazioni per particelle con massa nulla con elicità invarianti ±s. Si determinano anche i relativi prodotti scalari invarianti.РеэюмеВкратце обсуждаются трудности, воэникаюшие при переходе к пределуm→;0 в уравнениях видаi(∂ψ/∂t)=H у с отличной от нуля массой частиц, в которых ψ преобраэуется согласно представлениюD(0,s)⊕D(s, 0) однородной группы Лорентца. Отмечается, что хотя Гамильтониан Я стремится к хорощо иэвестному выражению приm→0, но окончательное волновое уравнение является неудовлетворит ельным, так как инвариантное скалярное проиэведение (в пространстве рещений волнового уравнения) имеет неприемлемый вид. Мы обнаруживаем, что зта трудность обусловлена неприводимостью представления группы Пуанкаре череэ волновые функции, преобраэуюшиеся, какD(0,s)⊕D(s,0) в случае нулевой массы. Учитывая зтот факт, мы, по аналогии с рассмотрением для частиц с отличной от нуля массой, получаем волновое уравнение для частиц нулевой массы с инвариантными спиральностями ±s. Также определяются соответствуюшие инвариантные скалярные проиэведения.