TY - JOUR
T1 - Search for gamma-ray emission from p -wave dark matter annihilation in the Galactic Center
AU - Johnson, C.
AU - Caputo, R.
AU - Karwin, C.
AU - Murgia, S.
AU - Ritz, S.
AU - Shelton, J.
N1 - The authors would like to thank Bill Atwood for numerous helpful discussions. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include NASA and the Department of Energy in the United States; the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy; the Ministry of Education, Culture, Sports, Science and Technology and High Energy Accelerator Research Organization and Japan Aerospace Exploration Agency in Japan; and the K. A. Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. Resources supporting this work were provided by the NASA High-End Computing Program through the NASA Advanced Supercomputing Division at Ames Research Center. The work of J. S. was supported by DOE Grants No. DE-SC0015655 and No. DE-SC0017840.
PY - 2019/5/15
Y1 - 2019/5/15
N2 - Indirect searches for dark matter through Standard Model products of its annihilation generally assume a cross section which is dominated by a term independent of velocity (s-wave annihilation). However, in many dark matter (DM) models, an s-wave annihilation cross section is absent or helicity suppressed. To reproduce the correct DM relic density in these models, the leading term in the cross section is proportional to the DM velocity squared (p-wave annihilation). Indirect detection of such p-wave DM is difficult because the average velocities of DM in galaxies today are orders of magnitude slower than the DM velocity at the time of decoupling from the primordial thermal plasma, thus suppressing the annihilation cross section today by some 5 orders of magnitude relative to its value at freeze-out. Thus p-wave DM is out of reach of traditional searches for DM annihilations in the Galactic halo. Near the region of influence of a central supermassive black hole, such as Sgr A∗, however, DM can form a localized overdensity known as a "spike." In such spikes, the DM is predicted to be both concentrated in space and accelerated to higher velocities, thereby allowing the γ-ray signature from its annihilation to potentially be detectable above the background. We use the Fermi Large Area Telescope to search for the γ-ray signature of p-wave annihilating DM from a spike around Sgr A∗ in the energy range 10-600 GeV. Such a signal would appear as a point source and would have a sharp line or boxlike spectral features difficult to mimic with standard astrophysical processes, indicating a DM origin. We find no significant excess of γ rays in this range, and we place upper limits on the flux in γ-ray boxes originating from the Galactic Center. This result, the first of its kind, is interpreted in the context of different models of the DM density near Sgr A∗.
AB - Indirect searches for dark matter through Standard Model products of its annihilation generally assume a cross section which is dominated by a term independent of velocity (s-wave annihilation). However, in many dark matter (DM) models, an s-wave annihilation cross section is absent or helicity suppressed. To reproduce the correct DM relic density in these models, the leading term in the cross section is proportional to the DM velocity squared (p-wave annihilation). Indirect detection of such p-wave DM is difficult because the average velocities of DM in galaxies today are orders of magnitude slower than the DM velocity at the time of decoupling from the primordial thermal plasma, thus suppressing the annihilation cross section today by some 5 orders of magnitude relative to its value at freeze-out. Thus p-wave DM is out of reach of traditional searches for DM annihilations in the Galactic halo. Near the region of influence of a central supermassive black hole, such as Sgr A∗, however, DM can form a localized overdensity known as a "spike." In such spikes, the DM is predicted to be both concentrated in space and accelerated to higher velocities, thereby allowing the γ-ray signature from its annihilation to potentially be detectable above the background. We use the Fermi Large Area Telescope to search for the γ-ray signature of p-wave annihilating DM from a spike around Sgr A∗ in the energy range 10-600 GeV. Such a signal would appear as a point source and would have a sharp line or boxlike spectral features difficult to mimic with standard astrophysical processes, indicating a DM origin. We find no significant excess of γ rays in this range, and we place upper limits on the flux in γ-ray boxes originating from the Galactic Center. This result, the first of its kind, is interpreted in the context of different models of the DM density near Sgr A∗.
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U2 - 10.1103/PhysRevD.99.103007
DO - 10.1103/PhysRevD.99.103007
M3 - Article
C2 - 31535060
AN - SCOPUS:85066452579
SN - 2470-0010
VL - 99
JO - Physical Review D
JF - Physical Review D
IS - 10
M1 - 103007
ER -