International Journal of Modern Physics A

The Higgs field was first proposed almost 50 years ago. Twenty years ago the tools needed to discover the Higgs boson, the large hadron collider and the CMS and ATLAS experiments, were initiated. Data taking was begun in 2010 and culminated in the announcement of the discovery of a "Higgs-like" boson on 4 July 2012. This discovery completes the Standard Model (SM) of high energy physics, if it is indeed the hypothesized SM Higgs particle. Future data taking will explore the properties of the new 125 GeV particle to see if it has all the attributes of an SM Higgs and to explore the mechanism that maintains its "low" mass.

In this review, we discuss methods of parsing direct information from collider experiments regarding the Higgs boson and describe simple ways in which experimental likelihoods can be consistently reconstructed and interfaced with model predictions in pertinent parameter spaces. We review prevalent scenarios for extending the electroweak symmetry breaking sector and emphasize their predictions for nonstandard Higgs phenomenology that could be observed in large hadron collider (LHC) data if naturalness is realized in particular ways. Specifically we identify how measurements of Higgs couplings can be used to imply the existence of new physics at particular scales within various contexts. The most dominant production and decay modes of the Higgs-like state observed in the early data sets have proven to be consistent with predictions of the Higgs boson of the Standard Model, though interesting directions in subdominant channels still exist and will require our careful attention in further experimental tests. Slightly anomalous rates in certain channels at the early LHC have spurred effort in model building and spectra analyses of particular theories, and we discuss these developments in some detail. Finally, we highlight some parameter spaces of interest in order to give examples of how the data surrounding the new state can most effectively be used to constrain specific models of weak scale physics.

Here we reanalyze various quasiparticle models of quark gluon plasma from the statistical mechanics and thermodynamics point of view. We investigate the statistical mechanics and thermodynamics inconsistencies involved in these models and their consequences in the observables. Quasiparticle models are phenomenological models with few parameters and by adjusting them all models fit the results of lattice gauge simulation of gluon plasma [G. Boyd et al., Phys. Rev. Lett.75, 4169 (1995); G. Boyd et al., Nucl. Phys. B469, 419 (1996)]. However, after fixing two of the three parameters of the model by physical arguments, only one quasiparticle model, which is consistent with both statistical mechanics and thermodynamics, fits the Bielefeld lattice data [G. Boyd et al., Phys. Rev. Lett.75, 4169 (1995); G. Boyd et al., Nucl. Phys. B469, 419 (1996)]. The same model also fits the recent lattice results of Wuppertal–Budapest group [S. Borsanyi et al., arXiv:1204.6184v1 [hep-lat]], which deals with precision SU(3) thermodynamics for a large temperature range, reasonably well.

We use the phenomenological approach to study properties of space–time in the vicinity of the Schwarzschild black-hole singularity. Requiring finiteness of the Schwarzschild-like metrics we come to the notion of integrable singularity that is, in a sense, weaker than the conventional singularity and allows the (effective) matter to pass to the white-hole region. This leads to a possibility of generating a new universe there. Thanks to the gravitational field of the singularity, this universe is already born highly inflated ("singularity-induced inflation") before the ordinary inflation starts.

A single real scalar field of spin zero obeying the Klein–Gordon equation in flat space–time under external conditions is considered in the context of the spin-statistics connection. An imposed accelerated boundary on the field is made to become, in the far future, (1) asymptotically inertial and (2) asymptotically noninertial (with an infinite acceleration). The constant acceleration Unruh effect is also considered. The systems involving nontrivial Bogoliubov transformations contain dynamics which point to commutation relations. Particles described by in-modes obey the same statistics as particles described by out-modes. It is found in the nontrivial systems that the spin-statistics connection can be manifest from the acceleration. The equation of motion for the boundary which forever emits thermal radiation is revealed.

The current limits for fourth generation quarks allows to expect their mass of the order of 500 GeV. In this mass region for quark–antiquark pair the additional Yukawa-type attraction due to Higgs mechanism is expected to emerge. This Higgs-induced attraction greatly exceeds strong interaction between quarks and leads to the formation of bound states in both color-octet S⁽⁸⁾ and singlet S⁽¹⁾ states. In the key of recent works on significance of color-octet channel for production of color-singlet state of fourth generation we calculated the binding energies for both octet and singlet states. Such an attraction localizes quarks in extremely small area. Hence, color-octet pair of fourth generation quarks can form the "nucleus" and, together with color neutralizing light particle that is captured by strong interaction in orbit around the nucleus, create particle with structure similar to Deuterium.

We study the masses and decay constants of heavy–light flavor mesons D, D_s, B and B_s in a QCD potential model. The mesonic wave function is used to compute the masses of D and B mesons in the ground state and the wave function is transformed to momentum space to estimate the pseudoscalar decay constants of these mesons. The leptonic decay widths and branching ratio of these mesons for different leptonic channels are also computed to compare with the experimental values. The results are found to be compatible with available data.