Modern Physics Letters A

The mixing parameter ΔM_s is studied in the MSSM with large tan β. The recent Tevatron measurement of ΔM_s is used to constrain the MSSM parameter space. From this analysis the often neglected contribution to ΔM_s from the operator is found to be significant.

It is well known that the long-range nature of the Coulomb interaction makes the definition of asymptotic "in" and "out" states of charged particles problematic in quantum field theory. In particular, the notion of a simple particle pole in the vacuum charged particle propagator is untenable and should be replaced by a more complicated branch cut structure describing an electron interacting with a possibly infinite number of soft photons. Previous work suggests a Dirac propagator raised to a fractional power dependent upon the fine structure constant, however the exponent has not been calculated in a unique gauge-invariant manner. It has even been suggested that the fractal "anomalous dimension" can be removed by a gauge transformation. Here, a gauge-invariant non-perturbative calculation will be discussed yielding an unambiguous fractional exponent. The closely analogous case of soft graviton exponents is also briefly explored.

We consider the production of magnetic monopoles via γγ fusion at high energy pp collisions. In the assumption that the monopole spin is equal 0, 1/2, 1, the monopole–antimonopole pair production cross-section by this mechanism at LHC energies is estimated and analyzed.

In this study, the fragmentation production cross-sections of heavy residual nuclides in the reactions ²³⁸U(1 A GeV) + p and p (1.2 GeV) + ²³²Th were calculated and the production of more than 370 different isotopes for this incident reactions was presented. The calculations were made by using the Cascade-Exciton Model including pre-equilibrium effect, the Intranuclear Cascade Model, the empirical and the semi-empirical parametrization. The results of the cross-sections obtained were compared with available experimental data and examined the relation between each other. It is seen that the precision of this models to estimate residue production cross-sections is still far from the performance required for technical applications and this incident model should be improved to obtain a deeper understanding of the reaction mechanisms involved in the production of isotopes.

A nontrivial scalar solution, whose source is a massive scalar field with a double-well potential, for a non-rotating Bananas–Teitelboim–Zanelli (BTZ) black hole is obtained with a condition , where μ is the mass of scalar field and the cosmological constant. The stability of solution is also studied. The mass of black hole with a scalar hair is greater than the black hole without hair. The scalar solution proposes a regular horizon which hides the naked singularity.

As a continuum work of Bhaumik et al.³ who derived the common eigenvector of the number-difference operator Q≡(a^†a-b^†b) and pair-annihilation operator ab, we search for the simultaneous eigenvector of Q and (ab-a^†b^†) by setting up a complex differential equation in the bipartite entangled state representation. The differential equation is then solved in terms of the two-variable Hermite polynomials and the formal hypergeometric functions. The work is also an addendum to Ref. 5 in which the common eigenkets of Q and pair creators a^†b^† are discussed.