The effect of a light radion on the triviality bound on higgs mass

In this paper we study how the triviality bound on higgs mass in the context of the SM is modified by a light stabilized radion of the Goldberger-Wise variety. Our approach is inherently perturbative. Including the radion contribution to \bt(\l) and \bt(g_t) to one loop we evolve the higgs self coupling \l from the cut off \L(=\vphi) down to the EW scale $\mu_0 = v$. The triviality bound is obtained by requiring that \l(\L) = \sqrt{4 \pi} which is the perturbative limit. We also study the effect of small changes in the UVBC on the triviality bound both in the presence and absence of a light radion.Comment: 9 pages, latex, 2 eps figure

Identifying new physics contributions in the Higgs sector at linear e+e- colliders

Loop driven decay modes of the Higgs are sensitive to new physics contributions because of new particles in the loops. To highlight this we look at the dilepton-dijet signal in the dominant Higgs production channel at a linear e+e- collider. We show that by taking a simple ratio between cross-sections of two different final states such contributions can be very easily identified.Comment: Latex 4 pages, 2 eps figures (style files included). Talk given at the linear collider workshop LCWS06, Bangalore, March 200

How Do Glassy Domains Grow?

We construct the equations for the growth kinetics of a structural glass within mode-coupling theory, through a non-stationary variant of the 3-density correlator defined in Phys. Rev. Lett. 97}, 195701 (2006). We solve a schematic form of the resulting equations to obtain the coarsening of the 3-point correlator $\chi_3(t,t_w)$ as a function of waiting time $t_w$. For a quench into the glass, we find that $\chi_3$ attains a peak value $\sim t_w^{0.5}$ at $t -t_w \sim t_w^{0.8}$, providing a theoretical basis for the numerical observations of Parisi [J. Phys. Chem. B 103, 4128 (1999)] and Kob and Barrat [Phys. Rev. Lett. 78, 4581 (1997)]. The aging is not "simple": the $t_w$ dependence cannot be attributed to an evolving effective temperature.Comment: 6 pages, 5 figure

Modelling temporal and spatial features of collaboration network

The collaboration network is an example of a social network which has both non-trivial temporal and spatial dependence. Based on the observations of collaborations in Physical Review Letters, a model of collaboration network is proposed which correctly reproduces the time evolution of the link length distributions, clustering coefficients, degree distributions and assortative property of real data to a large extent.Comment: 8 pages, 10 figures; follow up work on arXiv.org/physics/0511181; accepted for publication in IJMP

Reentrant cluster glass and stability of ferromagnetism in Ga2MnCo Heusler alloy

We present here a detailed investigation into the magnetic ordering of full Heusler alloy Ga$_2$MnCo using dc, ac magnetization measurements, neutron diffraction and neutron depolarization experiments. Crystal structure at room temperature was first confirmed to be L2$_1$ using the highly intense synchrotron X-ray diffraction (XRD) technique. Temperature dependent magnetization reveals that Ga$_2$MnCo enters a ferromagnetic (FM) state at $T_C =$154 K, characterized by a sharp increase in magnetization and a plateau-like region hereafter. As the temperature is decreased further, a sharp drop in magnetization is observed at $T_f$ = 50 K, hinting towards an antiferromagnetic (AFM) phase change. Neutron diffraction (ND) recorded over the range of temperature from 6 to 300 K, provides combined information regarding crystal as well as magnetic structure. Accordingly, an increase in the intensity of the ND pattern is seen at 150 K, signaling onset of long range FM order. However, there is no sign of appearance of superlattice reflections corresponding to the AFM phase, in the patterns recorded below 50 K. An unusual discontinuity in the unit cell volume is seen around $T_f$ indicating a coupling of this second transition with the contraction of the lattice. Attempts to unravel this interesting magnetic behaviour using ac susceptibility measurements lead to the existence of glassy magnetism below $T_f$. Systematic analysis of the susceptibility results along with neutron depolarization measurement, identifies the low temperature phase as a reentrant cluster glass.Comment: 8 pages, 7 figures, published in Phys. Rev.

Muon anomaly and a lower bound on higgs mass due to a light stabilized radion in the Randall-Sundrum model

We investigate the Randall-Sundrum model with a light stabilized radion (required to fix the size of the extra dimension) in the light of muon anomalous magnetic moment $a_\mu [= \frac{(g - 2)}{2}]$. Using the recent data (obtained from the E821 experiment of the BNL collaboration) which differs by $2.6 \sigma$ from the Standard Model result, we obtain constraints on radion mass \mphi and radion vev \vphi. In the presence of a radion the beta functions \beta(\l) and $\beta(g_t)$ of higgs quartic coupling (\l) and top-Yukawa coupling ($g_t$) gets modified. We find these modified beta functions. Using these beta functions together with the anomaly constrained \mphi and \vphi, we obtain lower bound on higgs mass $m_h$. We compare our result with the present LEP2 bound on $m_h$.Comment: Version to be appeared in IJMP