117848193
Symmetry behavior of a higher-power self-interacting scalar field at finite temperature
We have generalized the finite-temperature treatment of the scalar field of Dolan and Jackiw up to the one-loop approximation by adding an extra term which is proportional to the sixth power of the field. The inclusion of such a term makes the theory nonrenormalizable. However, we have carried out, parallel to the renormalizable theory, a subtraction method which we call ''restricted renormalization'' in order to study the effect of the inclusion of this term. The critical temperature in the theory does not depend on the coupling constant kappa associated with the phi/sup 4/ term in the interaction. Also, the theory even at the phi/sup 4/ level depends on an integral parameter n, if we consider the critical-temperature equation as a complex equation. We are then forced to introduce different fields depending on the parameter n. However, not all n-values are allowed. Up to the approximation considered, the n-values have to be greater than 1.
119098723
Influence of collapsing matter on the enveloping expanding universe
Using a collapsing matter model at the center of an expanding universe as described by Weinberg we assume a special type of generated pressure. This pressure transmits into the surrounding expanding universe. Under certain restriction the ensuing hubble parameter is positive. The deacceleration parameter fluctuates with time, indicating that the universe accelerates for certain time and decelerates for other time intervals.
119298148
Compressed supersymmetry at 14 TeV LHC
In this work we study the collider phenomenology of a compressed supersymmetric model with gluino (e) and the lightest neutralino (e � 0 ). All other sparticles are assumed to be heavy. We consider gluino pair production at the 14 TeV LHC and present the mass reach of gluino as a function of mass splitting between gluino and the the lightest neutralino. We find that the gluino mass below 1 TeV can be excluded at 95% CL with integrated luminosity of 100 fb 1 for extreme degenerate case where mass separation between gluino and the lightest neutralino is about 20 GeV. On the other hand, the lower bound on the mass of gluino increases to 1.2 - 1.3 TeV if the mass splitting between the gluino and e � 0 is about 200 GeV. This result shows that for degenerate gluino, the current mass limit may extend approximately 400-500 GeV at 14 TeV LHC.
118682766
SUSY signals with small and large trilinear couplings at the LHC 7 TeV runs and neutralino dark matter
We propose the signal $1b+1l+N_j+\etslash$ along with appropriate selection criteria for the LHC 7 TeV run, where the number of jets $(N_j)$ is $\ge$ 2 or 4. These signals can complement the canonical $Jets + \etslash$ signature since they are sensitive to the trilinear soft breaking parameter $(A_0)$ and low values of the parameter tan$\beta$ in the minimal supergravity (mSUGRA) model. A large region of this mSUGRA parameter space within the reach of the ongoing experiments at the LHC is disfavoured by the bound on the lightest Higgs boson mass ($m_h \ge 114.4 $ GeV) unless $A_0$ has moderate to large negative values. Interestingly this parameter space with $A_0 \ne 0$ is also consistent with the observed dark matter relic density. A natural consequence of large $A_0$ is the existence of a light top squark ($\lstop$). The proposed signals primarily stem from direct $\lstop \lstop^*$ production and/or $\tilde g \ra \tilde t_{1} t $, if all squark-gluino events are considered. A thorough analysis of the signals and the corresponding backgrounds are presented using the event generator Pythia. We finally compare the signal size for $A_0 = 0$ and $A_0 \ne 0$.