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String Axiverse

ArXiv 0905.4720 (2009)

Authors:

Asimina Arvanitaki, Savas Dimopoulos, Sergei Dubovsky, Nemanja Kaloper, John March-Russell

Abstract:

String theory suggests the simultaneous presence of many ultralight axions possibly populating each decade of mass down to the Hubble scale 10^-33eV. Conversely the presence of such a plenitude of axions (an "axiverse") would be evidence for string theory, since it arises due to the topological complexity of the extra-dimensional manifold and is ad hoc in a theory with just the four familiar dimensions. We investigate how upcoming astrophysical experiments will explore the existence of such axions over a vast mass range from 10^-33eV to 10^-10eV. Axions with masses between 10^-33eV to 10^-28eV cause a rotation of the CMB polarization that is constant throughout the sky. The predicted rotation angle is of order \alpha~1/137. Axions in the mass range 10^-28eV to 10^-18eV give rise to multiple steps in the matter power spectrum, that will be probed by upcoming galaxy surveys. Axions in the mass range 10^-22eV to 10^-10eV affect the dynamics and gravitational wave emission of rapidly rotating astrophysical black holes through the Penrose superradiance process. When the axion Compton wavelength is of order of the black hole size, the axions develop "superradiant" atomic bound states around the black hole "nucleus". Their occupation number grows exponentially by extracting rotational energy from the ergosphere, culminating in a rotating Bose-Einstein axion condensate emitting gravitational waves. This mechanism creates mass gaps in the spectrum of rapidly rotating black holes that diagnose the presence of axions. The rapidly rotating black hole in the X-ray binary LMC X-1 implies an upper limit on the decay constant of the QCD axion f_a<2*10^17GeV, much below the Planck mass. This reach can be improved down to the grand unification scale f_a<2*10^16GeV, by observing smaller stellar mass black holes.
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String Axiverse

(2009)

Authors:

Asimina Arvanitaki, Savas Dimopoulos, Sergei Dubovsky, Nemanja Kaloper, John March-Russell
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Limits on a muon flux from neutralino annihilations in the sun with the IceCube 22-string detector.

Phys Rev Lett 102:20 (2009) 201302

Authors:

R Abbasi, Y Abdou, M Ackermann, J Adams, M Ahlers, K Andeen, J Auffenberg, X Bai, M Baker, SW Barwick, R Bay, JL Bazo Alba, K Beattie, JJ Beatty, S Bechet, JK Becker, K-H Becker, ML Benabderrahmane, J Berdermann, P Berghaus, D Berley, E Bernardini, D Bertrand, DZ Besson, M Bissok, E Blaufuss, DJ Boersma, C Bohm, J Bolmont, S Böser, O Botner, L Bradley, J Braun, D Breder, T Burgess, T Castermans, D Chirkin, B Christy, J Clem, S Cohen, DF Cowen, MV D'Agostino, M Danninger, CT Day, C De Clercq, L Demirörs, O Depaepe, F Descamps, P Desiati, G de Vries-Uiterweerd, T Deyoung, JC Diaz-Velez, J Dreyer, JP Dumm, MR Duvoort, WR Edwards, R Ehrlich, J Eisch, RW Ellsworth, O Engdegård, S Euler, PA Evenson, O Fadiran, AR Fazely, T Feusels, K Filimonov, C Finley, MM Foerster, BD Fox, A Franckowiak, R Franke, TK Gaisser, J Gallagher, R Ganugapati, L Gerhardt, L Gladstone, A Goldschmidt, JA Goodman, R Gozzini, D Grant, T Griesel, A Gross, S Grullon, RM Gunasingha, M Gurtner, C Ha, A Hallgren, F Halzen, K Han, K Hanson, Y Hasegawa, J Heise, K Helbing, P Herquet, S Hickford, GC Hill, KD Hoffman, K Hoshina, D Hubert, W Huelsnitz, J-P Hülss, PO Hulth, K Hultqvist, S Hussain, RL Imlay, M Inaba, A Ishihara, J Jacobsen, GS Japaridze, H Johansson, JM Joseph, K-H Kampert, A Kappes, T Karg, A Karle, JL Kelley, P Kenny, J Kiryluk, F Kislat, SR Klein, S Klepser, S Knops, G Kohnen, H Kolanoski, L Köpke, M Kowalski, T Kowarik, M Krasberg, K Kuehn, T Kuwabara, M Labare, S Lafebre, K Laihem, H Landsman, R Lauer, H Leich, D Lennarz, A Lucke, J Lundberg, J Lünemann, J Madsen, P Majumdar, R Maruyama, K Mase, HS Matis, CP McParland, K Meagher, M Merck, P Mészáros, E Middell, N Milke, H Miyamoto, A Mohr, T Montaruli, R Morse, SM Movit, K Münich, R Nahnhauer, JW Nam, P Niessen, DR Nygren, S Odrowski, A Olivas, M Olivo, M Ono, S Panknin, S Patton, C Pérez de Los Heros, J Petrovic, A Piegsa, D Pieloth, AC Pohl, R Porrata, N Potthoff, PB Price, M Prikockis, GT Przybylski, K Rawlins, P Redl, E Resconi, W Rhode, M Ribordy, A Rizzo, JP Rodrigues, P Roth, F Rothmaier, C Rott, C Roucelle, D Rutledge, D Ryckbosch, H-G Sander, S Sarkar, K Satalecka, S Schlenstedt, T Schmidt, D Schneider, A Schukraft, O Schulz, M Schunck, D Seckel, B Semburg, SH Seo, Y Sestayo, S Seunarine, A Silvestri, A Slipak, GM Spiczak, C Spiering, M Stamatikos, T Stanev, G Stephens, T Stezelberger, RG Stokstad, MC Stoufer, S Stoyanov, EA Strahler, T Straszheim, K-H Sulanke, GW Sullivan, Q Swillens, I Taboada, O Tarasova, A Tepe, S Ter-Antonyan, C Terranova, S Tilav, M Tluczykont, PA Toale, D Tosi, D Turcan, N van Eijndhoven, J Vandenbroucke, A Van Overloop, B Voigt, C Walck, T Waldenmaier, M Walter, C Wendt, S Westerhoff, N Whitehorn, CH Wiebusch, A Wiedemann, G Wikström, DR Williams, R Wischnewski, H Wissing, K Woschnagg, XW Xu, G Yodh, S Yoshida, IceCube Collaboration

Abstract:

A search for muon neutrinos from neutralino annihilations in the Sun has been performed with the IceCube 22-string neutrino detector using data collected in 104.3 days of live time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured neutralinos in the Sun and converted to limits on the weakly interacting massive particle (WIMP) proton cross sections for WIMP masses in the range 250-5000 GeV. These results are the most stringent limits to date on neutralino annihilation in the Sun.
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Quasinormal modes of black holes and black branes

(2009)

Authors:

Emanuele Berti, Vitor Cardoso, Andrei O Starinets
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Testing astrophysical models for the PAMELA positron excess with cosmic ray nuclei

(2009)

Authors:

Philipp Mertsch, Subir Sarkar
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