Highly Charged Ions in a Dilute Plasma: An Exact Asymptotic Solution Involving Strong Coupling

The ion sphere model introduced long ago by Salpeter is placed in a rigorous theoretical setting. The leading corrections to this model for very highly charged but dilute ions in thermal equilibrium with a weakly coupled, one-component background plasma are explicitly computed, and the subleading corrections shown to be negligibly small. This is done using effective field theory methods advocated by Brown and Yaffe. Thus, corrections to nuclear reaction rates that such highly charged ions may undergo can be computed precisely. Moreover, their contribution to the equation of state can also be computed with precision. Such analytic results for very strong coupling are rarely available, and they can serve as benchmarks for testing computer models in this limit.Comment: 23 pages, 2 figures. To be published in Physical Review E. Expanded discussion of the equation of state included for clarit

Rigorous theory of nuclear fusion rates in a plasma

Real-time thermal field theory is used to reveal the structure of plasma corrections to nuclear reactions. Previous results are recovered in a fashion that clarifies their nature, and new extensions are made. Brown and Yaffe have introduced the methods of effective quantum field theory into plasma physics. They are used here to treat the interesting limiting case of dilute but very highly charged particles reacting in a dilute, one-component plasma. The highly charged particles are very strongly coupled to this background plasma. The effective field theory proves that this mean field solution plus the one-loop term dominate; higher loop corrections are negligible even though the problem involves strong coupling. Such analytic results for very strong coupling are rarely available, and they can serve as benchmarks for testing computer models.Comment: 4 pages and 2 figures, presented at SCCS 2005, June 20-25, Moscow, Russi

Modeling hydrodynamic self-propulsion with Stokesian Dynamics. Or teaching Stokesian Dynamics to swim

We develop a general framework for modeling the hydrodynamic self-propulsion (i.e., swimming) of bodies (e.g., microorganisms) at low Reynolds number via Stokesian Dynamics simulations. The swimming body is composed of many spherical particles constrained to form an assembly that deforms via relative motion of its constituent particles. The resistance tensor describing the hydrodynamic interactions among the individual particles maps directly onto that for the assembly. Specifying a particular swimming gait and imposing the condition that the swimming body is force- and torque-free determine the propulsive speed. The body’s translational and rotational velocities computed via this methodology are identical in form to that from the classical theory for the swimming of arbitrary bodies at low Reynolds number. We illustrate the generality of the method through simulations of a wide array of swimming bodies: pushers and pullers, spinners, the Taylor=Purcell swimming toroid, Taylor’s helical swimmer, Purcell’s three-link swimmer, and an amoeba-like body undergoing large-scale deformation. An open source code is a part of the supplementary material and can be used to simulate the swimming of a body with arbitrary geometry and swimming gait

Bounds on the lightest Higgs boson mass with three and four fermion generations

We present lower bounds on the Higgs boson mass in the Standard Model with three and four fermion generations SM(3,4), as well as upper bounds on the lightest Higgs boson mass in the minimal supersymmetric extension of the SM with three and four generations MSSM(3,4). Our analysis utilizes the SM(3,4) renormalization-group-improved one-loop effective potential of the Higgs boson to find the upper bounds on the Higgs mass in the MSSM(3,4) while the lower bounds in the SM(3,4) are derived from considerations of vacuum stability. All the bounds increase as the degenerate fourth generation mass increases, providing more room in theory space that respects the increasing experimental lower limit of the Higgs mass.Comment: 24 pages, 10 figures, Some additional discussion added. Final version to be published in International Journal of Modern Physics

A model of CP Violation from Extra Dimension

We construct a realistic model of CP violation in which CP is broken in the process of dimensional reduction and orbifold compactification from a five dimensional theories with $SU(3)\times SU(3) \times SU(3)$ gauge symmetry. CP violation is a result of the Hosotani type gauge configuration in the higher dimension.Comment: 5 page

Geometric Origin of CP Violation in an Extra-Dimensional Brane World

The fermion mass hierarchy and finding a predictive mechanism of the flavor mixing parameters remain two of the least understood puzzles facing particle physics today. In this work, we demonstrate how the realization of the Dirac algebra in the presence of two extra spatial dimensions leads to complex fermion field profiles in the extra dimensions. Dimensionally reducing to four dimensions leads to complex quark mass matrices in such a fashion that CP violation necessarily follows. We also present the generalization of the Randall-Sundrum scenario to the case of a multi-brane, six-dimensional brane-world and discuss how multi-brane worlds may shed light on the generation index of the SM matter content.Comment: 24 pages, 1 figure; references adde

CP Violation from Dimensional Reduction: Examples in 4+1 Dimensions

We provide simple examples of the generation of complex mass terms and hence CP violation through dimensional reduction.Comment: 6 pages, typos corrected, 1 reference adde

Sum Rules of Neutrino Masses and CP Violation in the Four-Neutrino Mixing Scheme

We show that the commutator of lepton mass matrices is invariant under terrestial matter effects in the four-neutrino mixing scheme. A set of model-independent sum rules for neutrino masses, which may be generalized to hold for an arbitrary number of neutrino families, are for the first time uncovered. Useful sum rules for the rephasing-invariant measures of leptonic CP violation have also been found. Finally we present a generic formula of T-violating asymmetries and expect it to be applicable to the future long-baseline neutrino oscillation experiments.Comment: RevTex 8 pages. 3 references added. Phys. Rev. D (in printing

Report of the Beyond the MSSM Subgroup for the Tevatron Run II SUSY/Higgs Workshop

There are many low-energy models of supersymmetry breaking parameters which are motivated by theoretical and experimental considerations. Here, we discuss some of the lesser-known theories of low-energy supersymmetry, and outline their phenomenological consequences. In some cases, these theories have more gauge symmetry or particle content than the Minimal Supersymmetric Standard Model. In other cases, the parameters of the Lagrangian are unusual compared to commonly accepted norms (e.g., Wino LSP, heavy gluino LSP, light gluino, etc.). The phenomenology of supersymmetry varies greatly between the different models. Correspondingly, particular aspects of the detectors assume greater or lesser importance. Detection of supersymmetry and the determination of all parameters may well depend upon having the widest possible view of supersymmetry phenomenology.Comment: 78 pages, 49 figures, to appear in the Proceedings of the Tevatron Run II SUSY/Higgs Workshop. Editor: J. F. Gunion; BTMSSM Convenors: M. Chertok, H. Dreiner, G. Landsberg, J. F. Gunion, J.D. Well