Weakly interacting massive particles (WIMPs) are a theoretical class of particles that are excellent dark matter candidates. WIMP annihilation or decay may produce essentially monochromatic gamma rays detectable by the Fermi Large Area Telescope (LAT) against the astrophysical gamma-ray emission of the Galaxy. We have searched for spectral lines in the energy range 5-300 GeV using 3.7 years of data, reprocessed with updated instrument calibrations and an improved energy dispersion model compared to the previous Fermi-LAT Collaboration line searches. We searched in five regions selected to optimize sensitivity to different theoretically motivated dark matter density distributions. We did not find any globally significant lines in our a priori search regions and present 95% confidence limits for annihilation cross sections of self-conjugate WIMPs and decay lifetimes. Our most significant fit occurred at 133 GeV in our smallest search region and had a local significance of 3.3 standard deviations, which translates to a global significance of 1.5 standard deviations. We discuss potential systematic effects in this search, and examine the feature at 133 GeV in detail. We find that the use both of reprocessed data and of additional
Search for gamma-ray spectral lines with the Fermi Large Area Telescope and dark matter implications / Ackermann M; Ajello M; Albert A; Allafort A; Baldini L; Barbiellini G; Bastieri D; Bechtol K; Bellazzini R; Bissaldi E; Bloom ED; Bonamente E; Bottacini E; Brandt TJ; Bregeon J; Brigida M; Bruel P; Buehler R; Buson S; Caliandro GA; Cameron RA; Caraveo PA; Casandjian JM; Cecchi C; Charles E; Chaves RCG; Chekhtman A; Chiang J; Ciprini S; Claus R; Cohen-Tanugi J; Conrad J; Cutini S; DAmmando F; de Angelis A; de Palma F; Dermer CD; Digel SW; Di Venere L; Drell PS; Drlica-Wagner A; Essig R; Favuzzi C; Fegan SJ; Ferrara EC; Focke WB; Franckowiak A; Fukazawa Y; Funk S; Fusco P; Gargano F; Gasparrini D; Germani S; Giglietto N; Giordano F; Giroletti M; Glanzman T; Godfrey G; Gomez-Vargas GA; Grenier IA; Guiriec S; Gustafsson M; Hadasch D; Hayashida M; Hill AB; Horan D; Hou X; Hughes RE; Inoue Y; Izaguirre E; Jogler T; Kamae T; Knodlseder J; Kuss M; Lande J; Larsson S; Latronico L; Longo F; Loparco F; Lovellette MN; Lubrano P; Malyshev D; Mayer M; Mazziotta MN; McEnery JE; Michelson PF; Mitthumsiri W; Mizuno T; Moiseev AA; Monzani ME; Morselli A; Moskalenko IV; Murgia S; Nakamori T; Nemmen R; Nuss E; Ohsugi T; Okumura A; Omodei N; Orienti M; Orlando E; Ormes JF; Paneque D; Perkins JS; Pesce-Rollins M; Piron F; Pivato G; Raino S; Rando R; Razzano M; Razzaque S; Reimer A; Reimer O; Romani RW; Sanchez-Conde M; Schulz A; Sgro C; Siegal-Gaskins J; Siskind EJ; Snyder A; Spandre G; Spinelli P; Suson DJ; Tajima H; Takahashi H; Thayer JG; Thayer JB; Tibaldo L; Tinivella M; Tosti G; Troja E; Uchiyama Y; Usher TL; Vandenbroucke J; Vasileiou V; Vianello G; Vitale V; Winer BL; Wood KS; Wood M; Yang Z; Zaharijas G; Zimmer S. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - STAMPA. - 88:8(2013), pp. 082002.1-082002.34. [10.1103/PhysRevD.88.082002]
Search for gamma-ray spectral lines with the Fermi Large Area Telescope and dark matter implications
D'AMMANDO, FILIPPO;
2013
Abstract
Weakly interacting massive particles (WIMPs) are a theoretical class of particles that are excellent dark matter candidates. WIMP annihilation or decay may produce essentially monochromatic gamma rays detectable by the Fermi Large Area Telescope (LAT) against the astrophysical gamma-ray emission of the Galaxy. We have searched for spectral lines in the energy range 5-300 GeV using 3.7 years of data, reprocessed with updated instrument calibrations and an improved energy dispersion model compared to the previous Fermi-LAT Collaboration line searches. We searched in five regions selected to optimize sensitivity to different theoretically motivated dark matter density distributions. We did not find any globally significant lines in our a priori search regions and present 95% confidence limits for annihilation cross sections of self-conjugate WIMPs and decay lifetimes. Our most significant fit occurred at 133 GeV in our smallest search region and had a local significance of 3.3 standard deviations, which translates to a global significance of 1.5 standard deviations. We discuss potential systematic effects in this search, and examine the feature at 133 GeV in detail. We find that the use both of reprocessed data and of additionalI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
