119220991
Warm inflation in loop quantum cosmology: a model with a general dissipative coefficient
A general form of warm inflation with the dissipative coefficient $\ensuremath{\Gamma}={\ensuremath{\Gamma}}_{0}(\ensuremath{\phi}/{\ensuremath{\phi}}_{0}{)}^{n}(T/{\ensuremath{\tau}}_{0}{)}^{m}$ in loop quantum cosmology is studied. In this case, we obtain conditions for the existence of a warm inflationary attractor in the context of loop quantum cosmology by using the method of stability analysis. The two cases when the dissipative coefficient is independent ($m=0$) and dependent ($m\ensuremath{\ne}0$) on temperature are analyzed specifically. In the latter case, we use the new power spectrum which should be used when considering temperature dependence in the dissipative coefficient. We find that the thermal effect is enhanced in the case $mg0$. As in the standard inflation in loop quantum cosmology, we also reach the conclusion that quantum effect leaves a tiny imprint on the cosmic microwave background sky.
122770000
Quantum thermal effect of arbitrarily accelerating Kinnersley black hole
The Hawking radiation of an arbitrarily accelerating Kinnersley black hole is studied. We obtain the event horizon equation and the Hawking thermal spectrum formula. Both the location and the temperature of the event horizon depend on the time and the angles. We recover the well-known results when the acceleration vanishes.
119090641
VIOLATION OF STRONG ENERGY CONDITION IN EFFECTIVE LOOP QUANTUM COSMOLOGY
In loop quantum cosmology nonperturbative modification to a scalar matter field at short scales implies inflation which also means a violation of the strong energy condition. In the framework of effective Hamiltonian we discuss the issue of violation of the strong energy condition in the presence of quantum geometry potential. It is shown that the appearance of quantum geometry potential strengthens the violation of the strong energy condition in small volume regions. In the small volume regions superinflation can easily happen. Furthermore, when the evolution of the universe approaches the bounce scale, this trend of violating the strong energy condition can be greatly amplified.
119267273
Extension of warm inflation to non-canonical scalar fields
We extend the warm inflationary scenario to the case of the noncanonical scalar fields. The equation of motion and the other basic equations of this new scenario are obtained. The Hubble damped term is enhanced in noncanonical inflation. A linear stability analysis is performed to give the proper slow-roll conditions in warm noncanonical inflation. We study the density fluctuations in the new picture and obtain an approximate analytic expression of the power spectrum. The energy scale at the horizon crossing is depressed by both noncanonical effect and thermal effect, and so is the tensor-to-scalar ratio. Besides the synergy, the noncanonical effect and the thermal effect are competing in the case of the warm noncanonical inflation.
118389942
DYNAMICAL BEHAVIOR OF INTERACTING DARK ENERGY IN LOOP QUANTUM COSMOLOGY
The dynamical behaviors of interacting dark energy in loop quantum cosmology are discussed in this paper. Based on three defined dimensionless variables, we simplify the equations of the fixed points. The fixed points for interacting dark energy can be determined by the Friedmann equation coupled with the dynamical equations in Einstein cosmology. But in loop quantum cosmology, besides the Friedmann equation, the conversation equation also gives a constrain on the fixed points. The difference of stability properties for the fixed points in loop quantum cosmology and the ones in Einstein cosmology are also discussed.
124390551
Hawking effect in Vaidya-Bonner space-time
A new method determining the location and the temperature of event horizons of evaporating black holes is suggested. Both the Klein-Gordon equation and the Dirac equation are studied with the method in a Vaidya-Bonner space-time. These equations are reduced near the event horizon when the generalized tortoise coordinates are adopted. The location and the temperature of the event horizon are shown automatically. The first approximation of our result is the same as that obtained by using the calculation of the vacuum expectation value of the renormalized energy-momentum tensor when the evaporation of the black hole is very slow.
16593749
Recent Electroweak Results from the Tevatron
W and Z bosons are mainly produced via quark-antiquark annihilations at the Fermilab Tevatron collider. Precision measurements with these gauge bosons provide us with high precision tests of the Standard Model (SM) as well as indirect search for possible new physics beyond the SM. I present the recent electroweak measurements related to single W, Z boson and diboson productions from the CDF and D0 experiments at the Fermilab Tevatron collider.
118371318
The SM extension with color-octet scalars: diphoton enhancement and global fit of LHC Higgs data
A bstractIn light of the significant progress of the LHC to determine the properties of the Higgs boson, we investigate the capability of the Manohar-Wise model in explaining the Higgs data. This model extends the SM by one family of color-octet and isospin-doublet scalars, and it can sizably alter the coupling strengths of the Higgs boson with gluons and photons. We first examine the current constraints on the model, which are from unitarity, the LHC searches for the scalars and the electroweak precision data (EWPD). In implementing the unitarity constraint, we use the properties of the SU(3) group to simplify the calculation. Then in the allowed parameter space we perform a fit of the model, using the latest ATLAS and CMS data, respectively. We find that the Manohar-Wise model is able to explain the data with χ2 significantly smaller than the SM value. We also find that the current Higgs data, especially the ATLAS data, are very powerful in further constraining the parameter space of the model. In particular, in order to explain the γγ enhancement reported by the ATLAS collaboration, the sign of the hgg coupling is usually opposite to that in the SM.
109816638
The RPC-based proposal for the ATLAS forward muon trigger upgrade in view of super-LHC
The innermost station of the present ATLAS forward muon detector needs to be upgraded for the super-LHC. We present a proposal to replace it with a sandwiched detector composed of several layers of small-radius Monitored Drift Tube chambers (sMDT) for precision tracking measurement and two stations of multi-gap Resistive Plate Chambers (mRPC) for triggering purpose. We describe the layout of the upgraded detector and the trigger strategy. Several modifications to the RPCs used in the ATLAS barrel region are needed to satisfy the super-LHC requirements. Various studies with the proposed mRPC timing resolution, spatial resolution and rate capability have been performed.
118462765
Dark matter in the little Higgs model under current experimental constraints from the LHC, Planck, and Xenon data
We examine the status of dark matter (heavy photon) in the littlest Higgs model with T parity (LHT) in light of the new results from the LHC Higgs search, the Planck dark matter relic density, and the XENON100 limit on the dark matter scattering off the nucleon. We obtain the following observations: (i) For the LHC Higgs data, the LHT can well be consistent with the CMS results but disfavored by the ATLAS observation of diphoton enhancement; (ii) for the dark matter relic density, the heavy photon in the LHT can account for the Planck data for the small mass splitting of mirror lepton and heavy photon; (iii) for the dark matter scattering off the nucleon, the heavy photon can give a spin-independent cross section below the XENON100 upper limit for m(AH) > 95 GeV (f > 665 GeV); (iv) a fit using the CMS Higgs data gives the lowest chi square of 2.63 (the standard model value is 4.75) at f similar or equal to 1120 GeV and m(AH) similar or equal to 170 GeV (at this point, the dark matter constraints from Planck and XENON100 can also be satisfied). Such a best point and its nearby favored region (even for an f value up to 3.8 TeV) can be covered by the future XENON1T (2017) experiment.
118505781
A SM-like Higgs near 125 GeV in low energy SUSY: a comparative study for MSSM and NMSSM
A bstractMotivated by the recent LHC hints of a Higgs boson around 125 GeV, we assume a SM-like Higgs with the mass 123-127 GeV and study its implication in low energy SUSY by comparing the MSSM and NMSSM. We consider various experimental constraints at 2σ level (including the muon g − 2 and the dark matter relic density) and perform a comprehensive scan over the parameter space of each model. Then in the parameter space which is allowed by current experimental constraints and also predicts a SM-like Higgs in 123-127 GeV, we examine the properties of the sensitive parameters (like the top squark mass and the trilinear coupling At) and calculate the rates of the di-photon signal and the V V* (V = W, Z) signals at the LHC. Our typical findings are: (i) In the MSSM the top squark and At must be large and thus incur some fine-tuning, which can be much ameliorated in the NMSSM; (ii) In the MSSM a light stau is needed to enhance the di- photon rate of the SM-like Higgs to exceed its SM prediction, while in the NMSSM the di-photon rate can be readily enhanced in several ways; (iii) In the MSSM the signal rates of pp → h → V V* at the LHC are never enhanced compared with their SM predictions, while in the NMSSM they may get enhanced significantly; (iv) A large part of the parameter space so far survived will be soon covered by the expected XENON100(2012) sensitivity (especially for the NMSSM).