2,047 research outputs found
Proposing "b-Parity" - a New Approximate Quantum Number in Inclusive b-jet Production - as an Efficient Probe of New Flavor Physics
We consider the inclusive reaction \ell^+ \ell^- -> nb +X (n = number of
b-jets) in lepton colliders for which we propose a useful approximately
conserved quantum number b_P=(-1)^n that we call b-Parity (b_P). We make the
observation that the Standard Model (SM) is essentially b_P-even since SM
b_P-violating signals are necessarily CKM suppressed. In contrast new flavor
physics can produce b_P=-1 signals whose only significant SM background is due
to b-jet misidentification. Thus, we show that b-jet counting, which relies
primarily on b-tagging, becomes a very simple and sensitive probe of new flavor
physics (i.e., of b_P-violation).Comment: 5 pages using revtex, 2 figures embadded in the text using epsfig. As
will appear in Phys.Rev.Lett.. Considerable improvement was made in the
background calculation as compared to version 1, by including purity
parameters, QCD effects and 4-jets processe
Property for noncommutative universal lattices
We establish a new spectral criterion for Kazhdan's property which is
applicable to a large class of discrete groups defined by generators and
relations. As the main application, we prove property for the groups
, where and is an arbitrary finitely generated
associative ring. We also strengthen some of the results on property for
Kac-Moody groups from a paper of Dymara and Januszkiewicz (Invent. Math 150
(2002)).Comment: 47 pages; final versio
Tuning spin-orbit coupling and superconductivity at the SrTiO3/LaAlO3 interface: a magneto-transport study
The superconducting transition temperature, Tc, of the SrTiO3/LaAlO3
interface was varied by the electric field effect. The anisotropy of the upper
critical field and the normal state magneto-transport were studied as a
function of gate voltage. The spin-orbit coupling energy is extracted. This
tunable energy scale is used to explain the strong gate dependence of the
mobility and of the anomalous Hall signal observed. The spin-orbit coupling
energy follows Tc for the electric field range under study
Direct Mass Limits for Chiral Fourth-Generation Quarks in All Mixing Scenarios
Present limits on chiral fourth-generation quark masses and
are broadly generalized and strengthened by combining both and decays
and considering the full range of and flavor-mixing scenarios (with
the lighter generations). Various characteristic mass-splitting choices are
considered. With we find that CDF limits on the mass
vary by no more than 10-20% with any choice of flavor-mixing, while for the
mass, we typically find stronger bounds, in some cases up to GeV. For we find GeV, depending on
the flavor-mixing and the size of the mass splitting
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