142 research outputs found
Phenomenological implications of light stop and higgsinos
We examine the phenomenological implications of light and
higgsinos in the Minimal Supersymmetric Standard Model, assuming and heavy and gauginos. In this simplified setting,
we study the contributions to , , , , , and their interplay.Comment: plain LATEX, 6 figures, 23 A4 page
Geometric Strategy for the Optimal Quantum Search
We explore quantum search from the geometric viewpoint of a complex
projective space , a space of rays. First, we show that the optimal quantum
search can be geometrically identified with the shortest path along the
geodesic joining a target state, an element of the computational basis, and
such an initial state as overlaps equally, up to phases, with all the elements
of the computational basis. Second, we calculate the entanglement through the
algorithm for any number of qubits as the minimum Fubini-Study distance to
the submanifold formed by separable states in Segre embedding, and find that
entanglement is used almost maximally for large . The computational time
seems to be optimized by the dynamics as the geodesic, running across entangled
states away from the submanifold of separable states, rather than the amount of
entanglement itself.Comment: revtex, 10 pages, 7 eps figures, uses psfrag packag
Analogue Models for T and CPT Violation in Neutral-Meson Oscillations
Analogue models for CP violation in neutral-meson systems are studied in a
general framework. No-go results are obtained for models in classical mechanics
that are nondissipative or that involve one-dimensional oscillators. A complete
emulation is shown to be possible for a two-dimensional oscillator with
rheonomic constraints, and an explicit example with spontaneous T and CPT
violation is presented. The results have implications for analogue models with
electrical circuits.Comment: 9 page
Energy-Charge Correlation in the Decay of and of Tagged Neutral Kaons
We relate the asymmetries in the charged pions energy in the decay into
of and of the tagged neutral kaons. The former
asymmetry is a given combination of , , and
. Moreover, the non-violating CP asymmetry allows a test for the
PT predictions within the Zel'dovich approach for the final state
interaction.Comment: 15 A4-pages LaTeX + 2 figures (available in hard copies from the
authors upon request to [email protected]), preprint DSF-93/52, SUHEP-58
Phenomenological Determination of the Beauty Meson Decay Parameter and the CP-Violating Angle
We fit the -matrix to all recent data with the following free
parameters: three mixing angles, the CP-violating angle in the Maiani
parametrisation, the top quark mass , and the product f_B{\cal
B}_{\B}^{1/2}, where is the -meson decay parameter and {\cal
B}_{\B} is the bag parameter. Our fits span a contiguous region in the
(f_B{\cal B}_{\B}^{1/2},\ \cos\delta)--plane, limited by 0.117\lsim f_B{\cal
B}_{\B}^{1/2}/{\rm GeV}\lsim 0.231 and --0.95 \lsim \lsim
0.70. The parameters f_B{\cal B}_{\B}^{1/2} and are strongly
positively correlated.Comment: 9 pages + 1 figure available upon request, HU-TFT-94-3
K -> pi pi and a light scalar meson
We explore the Delta-I= 1/2 rule and epsilon'/epsilon in K -> pi pi
transitions using a Dyson-Schwinger equation model. Exploiting the feature that
QCD penguin operators direct K^0_S transitions through 0^{++} intermediate
states, we find an explanation of the enhancement of I=0 K -> pi pi transitions
in the contribution of a light sigma-meson. This mechanism also affects
epsilon'/epsilon.Comment: 7 pages, REVTE
Measurements of Direct CP Violation, CPT Symmetry, and Other Parameters in the Neutral Kaon System
We present a series of measurements based on K -> pi+pi- and K -> pi0pi0
decays collected in 1996-1997 by the KTeV experiment (E832) at Fermilab. We
compare these four K -> pipi decay rates to measure the direct CP violation
parameter Re(e'/e) = (20.7 +- 2.8) x 10^-4. We also test CPT symmetry by
measuring the relative phase between the CP violating and CP conserving decay
amplitudes for K->pi+pi- (phi+-) and for K -> pi0pi0 (phi00). We find the
difference between the relative phases to be Delta-phi = phi00 - phi+- = (+0.39
+- 0.50) degrees and the deviation of phi+- from the superweak phase to be
phi+- - phi_SW =(+0.61 +- 1.19) degrees; both results are consistent with CPT
symmetry. In addition, we present new measurements of the KL-KS mass difference
and KS lifetime: Delta-m = (5261 +- 15) x 10^6 hbar/s and tauS = (89.65 +-
0.07) x 10^-12 s.Comment: Submitted to Phys. Rev. D, August 6, 2002; 37 pages, 32 figure
CPT, T, and Lorentz Violation in Neutral-Meson Oscillations
Tests of CPT and Lorentz symmetry using neutral-meson oscillations are
studied within a formalism that allows for indirect CPT and T violation of
arbitrary size and is independent of phase conventions. The analysis is
particularly appropriate for studies of CPT and T violation in oscillations of
the heavy neutral mesons D, B_d, and B_s. The general Lorentz- and CPT-breaking
standard-model extension is used to derive an expression for the parameter for
CPT violation. It varies in a prescribed way with the magnitude and orientation
of the meson momentum and consequently also with sidereal time. Decay
probabilities are presented for both uncorrelated and correlated mesons, and
some implications for experiments are discussed.Comment: 11 pages, references added, accepted in Physical Review
The Impact of |Delta I|=5/2 Transitions in K-> pi pi Decays
We consider the impact of isospin violation on the analysis of K-> pi pi
decays. We scrutinize, in particular, the phenomenological role played by the
additional weak amplitude, of |Delta I|=5/2 in character, incurred by the
presence of isospin violation. We show that Watson's theorem is appropriate in
O(m_d-m_u), so that the inferred pi-pi phase shift at sqrt{s}=m_K determines
the strong phase difference between the I=0 and I=2 amplitudes in K-> pi pi
decay. We find the magnitude of the |Delta I|=5/2 amplitude thus implied by the
empirical branching ratios to be larger than expected from estimates of
isospin-violating strong and electromagnetic effects. We effect a new
determination of the octet and 27-plet coupling constants with
strong-interaction isospin violation and with electromagnetic effects, as
computed by Cirigliano, Donoghue, and Golowich, and find that we are unable to
resolve the difficulty. Exploring the role of |Delta I|=5/2 transitions in the
CP-violating observable epsilon'/epsilon, we determine that the presence of a
|Delta I|=5/2 amplitude impacts the empirical determination of omega, the ratio
of the real parts of the |Delta I|=3/2 to |Delta I|=1/2 amplitudes, and that it
generates a decrease in the estimation of epsilon'/epsilon.Comment: 29 pages, 1 ps fig, refs. added, to appear in Phys. Rev.
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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