46556907
Detecting Boosted Dark Matter from the Sun with Large Volume Neutrino Detectors
We study novel scenarios where thermal dark matter (DM) can be efficiently captured in the Sun and annihilate into boosted dark matter. In models with semi-annihilating DM, where DM has a non-minimal stabilization symmetry, or in models with a multi-component DM sector, annihilations of DM can give rise to stable dark sector particles with moderate Lorentz boosts. We investigate both of these possibilities, presenting concrete models as proofs of concept. Both scenarios can yield viable thermal relic DM with masses O(1)-O(100) GeV. Taking advantage of the energetic proton recoils that arise when the boosted DM scatters off matter, we propose a detection strategy which uses large volume terrestrial detectors, such as those designed to detect neutrinos or proton decays. In particular, we propose a search for proton tracks pointing towards the Sun. We focus on signals at Cherenkov-radiation-based detectors such as Super-Kamiokande (SK) and its upgrade Hyper-Kamiokande (HK). We find that with spin-dependent scattering as the dominant DM-nucleus interaction at low energies, boosted DM can leave detectable signals at SK or HK, with sensitivity comparable to DM direct detection experiments while being consistent with current constraints. Our study provides a new search path for DM sectors with non-minimal structure.
119293046
ENTROPIC FORCE AND ITS FLUCTUATION IN EUCLIDEAN QUANTUM GRAVITY
In this paper, we study the idea about gravity as entropic force proposed by Verlinde. By interpreting Euclidean gravity in the language of thermodynamic quantities on holographic screen, we find the gravitational force can be calculated from the change of entropy on the screen. We show that normal gravity calculation can be reinterpreted in the language of thermodynamic variables. We also study the fluctuation of the force and find the fluctuation acting on the point-like particle can never be larger than the expectation value of the force. For a black hole in AdS space, by gauge/gravity duality, the fluctuation may be interpreted as arising from thermal fluctuation in the boundary description. And for a black hole in flat space, the ratio between fluctuation and force goes to a constant at infinity.
53540874
Dark matter induced nucleon decay: model and signatures
A bstractIf dark matter (DM) carries anti-baryon number, a DM particle may annihilate with a nucleon by flipping to anti-DM. Inspired by Hylogenesis models, we introduce a single component DM model where DM is asymmetric and carries B and L as -1/2. It can annihilate with a nucleon to an anti-lepton and an anti-DM at leading order or with an additional meson at sub-leading order. Such signals may be observed in proton decay experiments. If DM is captured in the Sun, the DM induced nucleon decay can generate a large flux of anti-neutrinos, which could be observed in neutrino experiments. Furthermore, the anti-DM particle in the final state obtains a relatively large momentum (few hundred MeV), and escapes the Sun. These fast-moving anti-DM particles could also induce interesting signals in various underground experiments.
118460290
Radio for hidden-photon dark matter detection
We propose a resonant electromagnetic detector to search for hidden-photon dark matter over an extensive range of masses. Hidden-photon dark matter can be described as a weakly coupled “hidden electric field,” oscillating at a frequency fixed by the mass, and able to penetrate any shielding. At low frequencies (compared to the inverse size of the shielding), we find that the observable effect of the hidden photon inside any shielding is a real, oscillating magnetic field. We outline experimental setups designed to search for hidden-photon dark matter, using a tunable, resonant LC circuit designed to couple to this magnetic field. Our “straw man” setups take into consideration resonator design, readout architecture and noise estimates. At high frequencies, there is an upper limit to the useful size of a single resonator set by 1/ν. However, many resonators may be multiplexed within a hidden-photon coherence length to increase the sensitivity in this regime. Hidden-photon dark matter has an enormous range of possible frequencies, but current experiments search only over a few narrow pieces of that range. As a result, we find the potential sensitivity of our proposal is many orders of magnitude beyond current limits over an extensive range of frequencies, from 100more » Hz up to 700 GHz and potentially higher.« less
204895786
DEVELOPMENT OF SUPERCONDUCTING RADIO FREQUENCY CAVITIES AT SINAP
This paper will present the recent development of superconducting radio frequency cavities at Shanghai Institute of Applied Physics (SINAP). Firstly, Two KEKB type 500MHz single cell niobium cavities have been fabricated and one of them has been vertical tested successfully in 2010. The highest accelerating gradient higher than 10MV/m was obtained while the quality factor was better than 4E8 at 4.2K. Secondly, a new type of 500MHz single cell cavity has been designed which adopts the fluted beam pipe for higher order modes propagation and a coaxial type high power input coupler. Thirdly, a 500MHz 5-cell superconducting cavity with large aperture, enlarged beam pipe for HOM propagation and high r/Q value has been optimized which can be a candidate cavity for high current FEL and ERL.