Limits on large extra dimensions based on observations of neutron stars with the Fermi-LAT

Journal Article · Wed Feb 01 00:00:00 EST 2012 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2012/02/012· OSTI ID:22279743

Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Buehler, R.; Cameron, R. A. ^[1]; Baldini, L.; Bellazzini, R.; Bregeon, J. ^[2]; Barbiellini, G. ^[3]; Bastieri, D.; Buson, S. ^[4]; Bonamente, E.; Cecchi, C. ^[5]; Brigida, M. ^[6]; Bruel, P. ^[7]; Caliandro, G. A. ^[8]; Caraveo, P. A. ^[9]; others, and

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1. W.W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
2. INFN — Sezione di Pisa, I-56127 Pisa (Italy)
3. INFN — Sezione di Trieste, I-34127 Trieste (Italy)
4. INFN — Sezione di Padova, I-35131 Padova (Italy)
5. INFN — Sezione di Perugia, I-06123 Perugia (Italy)
6. Dipartimento di Fisica 'M. Merlin' dell'Università e del Politecnico di Bari, I-70126 Bari (Italy)
7. Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, Palaiseau (France)
8. Institut de Ciències de l'Espai (IEEE-CSIC), Campus UAB, 08193 Barcelona (Spain)
9. INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, I-20133 Milano (Italy)

We present limits for the compactification scale in the theory of Large Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi Large Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the large fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to γγ should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.

• OSTI ID: 22279743
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2012, Issue 02; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
COMPACTIFICATION
COMPARATIVE EVALUATIONS
CORRECTIONS
COSMOLOGY
GAMMA RADIATION
GRAVITONS
KALUZA-KLEIN THEORY
MAXIMUM-LIKELIHOOD FIT
MONTE CARLO METHOD
NEUTRON STARS
PARTICLE PRODUCTION
TEV RANGE