119264552
Status of dark matter detection
The detection of dark matter has made great progresses in recent years.We give a brief review on the status and progress in dark matter detection, including the progresses in direct detection, collider detection at LHC and focus on the indirect detection. The results from PAMELA, ATIC, Fermi-LAT and relevant studies on these results are introduced. Then we give the progress on indirect detection of gamma rays from Fermi-LAT and ground based Cerenkov telescopes. Finally the detection of neutrinos and constraints on the nature of dark matter are reviewed briefly.
119303268
Detecting light stop pairs in coannihilation scenarios at the LHC
In this work, we study the light stop pair signals at the Large Hadron Collider (LHC) in three coannihilation scenarios, where the neutralino can coannihilate with the stop, chargino and stau, respectively, so as to yield the desired dark matter relic density. Signatures of the first scenario can be probed at the LHC via the associated jet production processes pp -> j + (t) over tilde(t) over tilde* by tagging an energetic monojet and a large missing transverse energy. The signatures of the other two scenarios can be searched via the pair production process pp -> (t) over tilde(t) over tilde* by tagging energetic b jets in the final states and a large missing transverse energy. We find that the LHC results at 7 TeV with 5 fb(-1) of data can exclude the stop mass up to 220, 380, and 220 GeV for these three scenarios, respectively. While the 20 fb(-1) data set at 8 TeV is considered, the LHC can be expected to exclude the stop mass up to 340, 430, and 370 GeV. DOI: 10.1103/PhysRevD.87.055007
118487966
Detecting interactions between dark matter and photons at high energy e(+)e(-) colliders
We investigate the sensitivity to the effective operators describing interactions between dark matter particles and photons at future high energy e+e(-) colliders via the gamma + is not an element of channel. Such operators could be useful to interpret the potential gamma-ray line signature observed by the Fermi-LAT. We find that these operators can be further tested at e(+)e(-) colliders by using either unpolarized or polarized beams. We also derive a general unitarity condition for 2 -> n processes and apply it to the dark matter production process e(+)e(-) -> chi chi gamma.
118600674
Detecting light leptophilic gauge boson at BESIII detector
Abstract The O ( GeV ) extra U ( 1 ) gauge boson named U-boson, has been proposed to mediate the interaction among leptons and dark matter (DM), in order to account for the observations by PAMELA and ATIC. In such kind of models, the extra U ( 1 ) gauge group can be chosen as U ( 1 ) L i − L j with L i the i -th generation lepton number. This anomaly-free model provides appropriate dark matter relic density and boost factor required by experiments. In this work the observability of such kind of U-boson at BESIII detector is investigated through the processes e + e − → U γ , followed by U → e + e − , U → μ + μ − and U → ν ν ¯ . In the invisible channel where U-boson decays into neutrinos, BESIII can measure the coupling of the extra U ( 1 ) down to O ( 10 − 4 ) ∼ O ( 10 − 5 ) because of the low Standard Model backgrounds. In the visible channel where U-boson decays into charged lepton pair, BESIII can only measure the coupling down to O ( 10 − 3 ) ∼ O ( 10 − 4 ) due to the large irreducible QED backgrounds.
119309338
Neutrino Signals from Solar Neutralino Annihilations in Anomaly Mediated Supersymmetry Breaking Model
The lightest neutralino, as the dark matter candidate, can be gravitationally captured by the Sun. In this paper, we studied the high energy neutrino signals from solar neutralino annihilations in the core of the Sun in the anomaly mediated supersymmetry breaking (AMSB) model. Based on the event-by-event Monte Carlo simulation code WimpSim, we studied the detailed energy and angular spectrum of the final muons at large neutrino telescope IceCube. More precisely, we simulated the processes since the production of neutrino via neutralino annihilation in the core of the Sun, neutrino propagation from the Sun to the Earth, as well as the converting processes from neutrino to muon. Our results showed that in the AMSB model it is possible to observe the energetic muons at IceCube, provided that the lightest neutralino has a relatively large Higgsino component, as a rule of thumb N{sub 13}{sup 2}+N{sub 14}{sup 2}>4%, or equivalently, {sigma}{sub SD}>10{sup -5} pb. Especially, for our favorable parameters the signal annual events can reach 102, and the statistical significance can reach more than 20. We pointed out that the energy spectrum of muons may be used to distinguish among the AMSB model and other supersymmetry breaking scenarios.
118441224
Probing light stop pairs at the LHC
In this work, we study the light stop pair signals at the LHC. We explore the supersymmetry parameter space with nonuniversal gaugino and third-generation masses at the grand unified theory scale. Recent LHC supersymmetry search results based on 35 pb(-1) and 1 fb(-1) of data are implemented to put the limits on stop pair events. The dark matter relic density and direct detection constraints are also taken into account. Detailed simulations on the signals and background for some benchmark points are performed, and it is found that the stop pair signals usually escape the LHC search if the present cut conditions are used. We also explore the potential and sensitivity of ILC to probe such scenarios. It is found that the ILC can detect them with an integrated luminosity of a few tens of fb(-1).
119122669
Effect of tensor correlations on the depletion of nuclear Fermi sea within the extended BHF approach
We have investigated the effect of tensor correlations on the depletion of nuclear Fermi sea in symmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach by adopting the AV18 two-body interaction and a microscopic three-body force. The contributions from various partial wave channels including the isospin-singlet T=0 channel, the isospin-triplet T=1 channel and the T=0 tensor 3SD1 channel have been calculated. The T=0 neutron-proton correlations play a dominated role in causing the depletion of nuclear Fermi sea. The T=0 correlation-induced depletion turns out to stem almost completely from the $^3SD_1$ tensor channel. The isospin-singlet T=0 3SD1 tensor correlations is shown to response for most of the depletion, which amounts to more than 70 percent out of the total depletion in the density region considered. The TBF turns out to leads to an enhancement of the depletion at high densities well above the empirical saturation density and its effect increases as a function of density.
119110371
Three-body force effect on off-shell mass operator and spectral functions in nuclear matter
Within the framework of the Brueckner theory, the off-shell behaviors of the mass operator $M(k,\omega)=V(k,\omega)+iW(k,\omega)$, i.e., its dependence upon the momentum $k$ and upon the nucleon frequency $\omega$, are investigated by including nuclear three-body force (TBF). The first two terms of the hole-line expansion of the mass operator are taken into account. The TBF effects on their off-shell properties are discussed. A comparison is made between the on-shell and off-shell values of $M_{1}$. The nucleon spectral function and nucleon momentum distribution are also calculated, and the calculation shows that they are hardly affected by the TBF effect at the saturation density. At a high density two times greater than the saturation density, inclusion of the TBF may lead to a visible effect on the spectral function and may enhance the depletion of the hole states.
118365937
Three-body force effect on nucleon momentum distributions in asymmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach
We have investigated the three-body force (TBF) effect on the neutron and proton momentum distributions in asymmetric nuclear matter within the framework of the extended Brueckner-Hartree-Fock approach by adopting the $AV18$ two-body interaction plus a microscopic TBF. In asymmetric nuclear matter, it is shown that the neutron and proton momentum distributions become different from their common distribution in symmetric nuclear matter. The predicted depletion of the proton hole states increases while the neutron one decreases as a function of isospin asymmetry. The TBF effect on the neutron and proton momentum distributions turns out to be negligibly weak at low densities around and below the normal nuclear density. The TBF effect is found to become sizable only at high densities well above the saturation density, and inclusion of the TBF leads to an overall enhancement of the depletion of the neutron and proton Fermi seas.