Professor, Physics & Astronomy, UCLA

Senior Scientist, IPMU, U. of Tokyo, Japan

Office: 4-915, PAB (click to see the map)
Email:
PGP/GnuPG public key

Phone: +1-970-KUSENKO (+1-970-587-3656)

Calendar (free/busy times)

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Professor Kusenko received his undergraduate and graduate education at Moscow State University and ITP, Stony Brook, respectively. He held positions at University of Pennsylvania and at CERN Theory Division prior to joining UCLA. Professor Kusenko is a Fellow of American Physical Society and an active member of Aspen Center for Physics.

Seminars this week
Physics & Astronomy Colloquium
TEP seminars

TEP group
Physics and Astronomy at UCLA
Directions to UCLA

Intergalactic magnetic fields have been measured, for the first time, from the "fuzziness" of gamma-ray images [12]. These femtogauss fields permeate deep space between galaxies, possibly, since the time of the Big Bang.

Read an article in Science (2010), and also in UCLA News.

Ultrahigh-energy cosmic rays present a number of puzzles. It is difficult to understand why a single cosmic particle should carry as much energy as a bullet! Moreover, recent results from Pierre Auger Observatory indicate that many of these particles are nuclei, not protons. This implies that natural nuclear accelerators, such as Gamma Ray Bursts and other unusual stellar explosions, have taken place in our own Galaxy in the past [1].

Read about cosmic accelerators in UCLA News or in CERN Courier (2010), and about Inexplicable nuclei in Nature (2010).

Dark matter: sterile neutrinos, astrophysical hints, ongoing search. Most of the matter in the universe is dark matter, which is not made of ordinary atoms. The identity of dark matter particles remains a puzzle. A well-motivated candidate for such a particle is a right-handed or sterile neutrino, which is supported by several arguments and astrophysical hints [4]. First, right-handed neutrinos are needed to explain the observed masses of ordinary neutrinos, and the requisite mass can be naturally accommodated via the split seesaw mechanism [5]. Second, astrophysics of supernova explosions supports the existence of a sterile neutrino with mass of several keV: the asymmetric emission of such a particle from a cooling newly born neutron star could explain the long-standing puzzle of the origin of pulsar velocities [6]. Sterile neutrinos can also play a role in the formation of the first stars [7], and they may open a window on the new physics at the electroweak scale [8].
The first dedicated search for dark matter using X-ray telescopes is under way, and it has already produced an intriguing potential evidence of a 5-keV relic sterile neutrino [9]. This potential detection will be probed in the upcoming X-ray observations.

Read about sterile neutrinos, dark matter, and the pulsar kicks: Scientific American (2011), Nature (2010), Scientific American (2010), Nature (2006),  Economist (2006), New Scientist (2006), Popular Mechanics (2006), CERN Courier (2006) AIP Physics News Update, Sky and Telescope (1997), New Scientist (1996).

Q-balls are non-topological solitons that owe their stability to a conservation of some global charge. Baryonic Q-balls appear in every supersymmetric extension of the Standard Model [3]. If supersymmetry exists, stable Q-balls could be copiously produced at the end of inflation and may now exist as a form of dark matter [3].

Read a New Scientist article and also a story in AIP Physics News Update.

Baryogenesis. Although every particle has its antiparticle, there is no antimatter in the observed universe. The process in which the  matter-antimatter asymmetry was produced in the early universe, called  baryogenesis [10], remains a mystery. The asymmetry could have arisen from standard electroweak interactions at the end of inflation [11] or from leptogenesis. Another appealing scenario is Affleck-Dine baryogenesis, which can generate both ordinary matter and dark matter [10].

1. A. Calvez, A.Kusenko, and S. Nagataki, Phys. Rev. Lett. 105, 091101 (2010).

2. W. Essey and A.Kusenko, Astropart. Phys. 33, 81 (2010); W. Essey. O. Kalashev, A.Kusenko, and J. Beacom, Phys. Rev. Lett., 104, 141102 (2010); S. Ando and A. Kusenko, arXiv:1005.1924

3. A. Kusenko, Phys.Lett.B405:108,1997; A. Kusenko and M. Shaposhnikov, Phys.Lett.B418:46,1997

4. A. Kusenko, Phys. Rept. 481, 1 (2009).

5. A. Kusenko, F. Takahashi, and T. Yanagida, Phys. Lett. B, in press

6. A.Kusenko and G.Segre, Phys. Rev. Lett. 77, 4872 (1996); Phys. Lett. B396, 197 (1997); Phys. Rev. Lett. 79, 2751,(1997); Phys.Rev.D 59:061302,1999; G. Fuller, A. Kusenko, I.Mocioiu, S.Pascoli, Phys. Rev. D68, 103002 (2003); C. Fryer and A. Kusenko, ApJ.S 163, 335 (2006); A. Kusenko, B. P. Mandal, and A. Mukherjee, Phys. Rev. D77, 123009 (2008).

7. P. Biermann and A. Kusenko, Phys. Rev. Lett. 96, 091301 (2006); J.Stasielak, P. Biermann, and A. Kusenko, ApJ 654, 290 (2007).

8. A. Kusenko, Phys. Rev. Lett. 97, 241301 (2006); K. Petraki and A. Kusenko, Phys. Rev. D77, 065014 (2008).

9. M. Loewenstein and A. Kusenko, ApJ 714, 652 (2010).

10. M. Dine and A. Kusenko, Rev. Mod. Phys. 76, 1 (2004).

11. J.Garcia-Bellido, D.Grigorev, A.Kusenko, and M.Shaposhnikov, Phys. Rev. D60,123504 (1999); J.M.Cornwall and A.Kusenko, Phys. Rev. D61, 103510 (2000); J.M.Cornwall, D.Grigoriev, and A.Kusenko, Phys. Rev. D64, 123518 (2001).

12. S. Ando and A. Kusenko, ApJ. 722, L39 (2010).

List of publications from SPIRES