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Title: Very Degenerate Higgsino Dark Matter

Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC); High Energy Physics (HEP)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: arXiv:1607.04288
Country of Publication:
United States
Astrophysics, Phenomenology-HEP,HEPPH, ASTRO

Citation Formats

Chun, Eung Jin, and /Korea Inst. Advanced Study, Seoul. Very Degenerate Higgsino Dark Matter. United States: N. p., 2017. Web.
Chun, Eung Jin, & /Korea Inst. Advanced Study, Seoul. Very Degenerate Higgsino Dark Matter. United States.
Chun, Eung Jin, and /Korea Inst. Advanced Study, Seoul. Wed . "Very Degenerate Higgsino Dark Matter". United States. doi:.
title = {Very Degenerate Higgsino Dark Matter},
author = {Chun, Eung Jin and /Korea Inst. Advanced Study, Seoul},
abstractNote = {},
doi = {},
journal = {arXiv:1607.04288},
number = ,
volume = ,
place = {United States},
year = {Wed May 24 00:00:00 EDT 2017},
month = {Wed May 24 00:00:00 EDT 2017}
  • In this paper, we present a study of the Very Degenerate Higgsino Dark Matter (DM), whose mass splitting between the lightest neutral and charged components is O(1) MeV, much smaller than radiative splitting of 355 MeV. The scenario is realized in the minimal supersymmetric standard model by small gaugino mixings. In contrast to the pure Higgsino DM with the radiative splitting only, various observable signatures with distinct features are induced. First of all, the very small mass splitting makes (a) sizable Sommerfeld enhancement and Ramsauer-Townsend (RT) suppression relevant to ~1 TeV Higgsino DM, and (b) Sommerfeld-Ramsauer-Townsend effect saturate at lowermore » velocities v/c ≲ 10 -3. As a result, annihilation signals can be large enough to be observed from the galactic center and/or dwarf galaxies, while the relative signal sizes can vary depending on the locations of Sommerfeld peaks and RT dips. In addition, at collider experiments, stable chargino signatures can be searched for to probe the model in the future. Finally, DM direct detection signals, however, depend on the Wino mass; even no detectable signals can be induced if the Wino is heavier than about 10 TeV.« less
  • Motivated by a supersymmetric interpretation of the CDF {ital ee}{gamma}{gamma}+{ital E}/{sub {ital T}} event and the reported {ital Z}{r_arrow}{bar {ital bb}} excess at LEP, we analyze the implied Higgsino-like lightest supersymmetric partner as a cold dark matter candidate. We examine constraints and calculate its relic density, obtaining 0.05{lt}{Omega}{ital h}{sup 2}{lt}1. Thus it is a viable cold dark matter candidate, and we discuss its favorable prospects for laboratory detection. {copyright} {ital 1996 The American Physical Society.}
  • We reinvestigate the question of whether a light Higgsino-like neutralino is a viable dark matter candidate. To this end we compute the dominant one-loop corrections to the masses of the Higgsino-like states in the minimal supersymmetric standard model (MSSM), due to loops involving heavy quarks and their superpartners. We also calculate analogous corrections to the couplings of Higgsino-like neutralinos to Z and Higgs bosons. In the region of parameter space leading to high Higgsino purity of the lightest neutralino, these corrections can change the expected relic density by up to a factor of 5 in either direction. We conclude thatmore » for favorable choices of soft supersymmetry-breaking parameters, a state with more than 99{percent} Higgsino purity could indeed form all cold dark matter in the Universe. In some cases these corrections can also increase the expected cross section for LSP scattering off spinless nuclei by up to two orders of magnitude, or reduce it to zero. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We analyze the CERN LEP constraints from searches for charginos {chi}{sup {plus_minus}} and neutralinos {chi}{sub i}, taking into account radiative corrections to the relations between their masses and the underlying Higgs-mixing and gaugino-mass parameters {mu}, m{sub 1/2}, and the trilinear mass parameter A{sub t}. While radiative corrections do not alter the excluded domain in m{sub {chi}{sup {plus_minus}}} as a function of m{sub {chi}{sup {plus_minus}}}{minus}m{sub {chi}}, its mapping into the {mu}, m{sub 1/2} plane is altered. We update our previous lower limits on the mass of gaugino dark matter and on tanthinsp{beta}, the ratio of Higgs vacuum expectation values, in lightmore » of the latest LEP data and these radiative corrections. We also discuss the viability of Higgsino dark matter, incorporating coannihilation effects into the calculation of the Higgsino relic abundance. We find that Higgsino dark matter is viable for only a very limited range of {mu} and m{sub 1/2}, which will be explored completely by upcoming LEP runs. {copyright} {ital 1998} {ital The American Physical Society}« less
  • No abstract prepared.