arXiv subjects

B. Qureshi

Publications and source records attributed to B. Qureshi.

3 recordsLinked to original sources

arXiv2023

Violation of the Landau-Yang theorem from Infrared Lorentz Symmetry Breaking

Lorentz symmetry forbids decays of massive spin-1 particle like the $Z^0$ into two massless photons, a result known as the Landau-Yang theorem. But it is known that infrared effects can break Lorentz invariance. Employing the construction of Mund et. al. \cite{MRS} which incorporated this Lorentz violation, we propose an interaction leading to the decay $Z^0 \rightarrow 2 γ$ and study the dependence of the decay on the parameter of this Lorentz violation.

hep-ph↗

arXiv2005

SUSY anomalies break N=2 to N=1: The supersphere and the fuzzy supersphere

The N=1 SUSY on S^2 and its fuzzy finite-dimensional matrix version are known. The latter regulates quantum field theories, and seems suitable for numerical work and capable of higher dimensional generalizations. In this paper, we study their instanton sectors. They are SUSY generalizations of U(1) bundles on S^2 and their fuzzy versions, and can be characterized by $k\in\mathbb{Z}$, the SUSY Chern numbers. In the no-instanton sector (k=0), N=2 SUSY can be chirally realized, the 3 new N=2 generators anticommuting with the ``Dirac'' operator defining the free action. If $k\neq 0$, the Dirac operator has zero modes which form an N=1 supermultiplet and an atypical representation of N=2 SUSY. They break the chiral SUSY generators by the Fujikawa mechanism. We have not found this mechanism for SUSY breakdown in the literature. All these phenomena occur also on the supersphere SUSY, the graded commutative limit of the fuzzy model. We plan to discuss that as well in a later work.

hep-th↗

arXiv2005

UV-IR Mixing in Non-Commutative Plane

Poincaré-invariant quantum field theories can be formulated on non-commutative planes if the coproduct on the Poincaré group is suitably deformed \cite{Dimitrijevic:2004rf, Chaichian:2004za}.(See also especially Oeckl \cite{Oeckl:1999jun},\cite{Oeckl:2000mar} and Grosse et al.\cite{Grosse:2001mar}) As shown in \cite{Balachandran:2005eb}, this important result of these authors implies modification of free field commutation and anti-commutation relations and striking phenomenological consequences such as violations of Pauli principle \cite{Balachandran:2005eb,Bal3}. In this paper we prove that with these modifications, UV-IR mixing disappears to all orders in perturbation theory from the $S$-Matrix. This result is in agreement with the previous results of Oeckl \cite{Oeckl:2000mar}.

hep-th↗