Exploring Novel Signatures in Direct Neutralino Searches

Abstract

Abstract. Since the expected rates for neutralino-nucleus scattering are expected to be small, one should exploit all the characteristic signatures of this reaction. Such are: (i) In the standard recoil measurements the modulation of the event rate due to the Earth's motion. (ii) In directional recoil experiments the correlation of the event rate with the sun's motion. One now has both modulation, which is much larger and depends not only on time, but on the direction of observation as well, and a large forward-backward asymmetry. (iii) In non recoil experiments gamma rays following the decay of excited states populated during the Nucleus-LSP collision. Branching ratios of about 6 percent are possible (iv) novel experiments in which one observes the electrons produced during the collision of the LSP with the nucleus. Branching ratios of about 10 per cent are possible.

Theoretical direct WIMP detection rates for transitions to the first excited state inKr83

“…The above upper cut-off value in the M-B is usually put in by hand. Such a cut-off comes in naturally, however, in the case of velocity distributions obtained from the halo WIMP mass density in the Eddington approach [63], which, in certain models, resemble a M-B distribution [64].…”

Inelastic WIMP-nucleus scattering to the first excited state in125Te

“…The above upper cut-off value in the M-B is usually put in by hand. Such a cut-off comes in naturally, however, in the case of velocity distributions obtained from the halo WIMP mass density in the Eddington approach [83], which, in certain models, resemble a M-B distribution [84].…”

One needs positive signatures for detection of Dark Matter

“…Nevertheless, for example, neutrons (and any other heavy neutral particle) can also produce nuclear recoils. There are also proposals which rely on WIMP detection via electron recoils [46,47].Due to the extremely rare event rate of the WIMP-nucleus interactions (the mean free path of a WIMP in matter is of the order of a light year), one can expect two features. One is that the probability of two consecutive interactions in a single detector or two closely located detectors is completely negligible.…”

“…In these directional recoil experiments it is planned to measure the correlation of the event rate with the Sun's motion [47][48][49]. Unfortunately, the task is extremely complicated [50][51][52][53][54].…”

“…Nevertheless, for example, neutrons (and any other heavy neutral particle) can also produce nuclear recoils. There are also proposals which rely on WIMP detection via electron recoils [46,47].…”