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Study of electron and neutrino interactions
This is the final report for the DOE-sponsored experimental particle physics program at Virginia Tech to study the properties of the Standard Model of strong and electroweak interactions. This contract (DE-AS05-80ER10713) covers the period from August 1, 1980 to January 31, 1993. Task B of this contract, headed by Professor Alexander Abashian, is described in this final report. This program has been pursued on many fronts by the researchers-in a search for axions at SLAC, in electron-positron collisions in the AMY experiment at the TRISTAN collider in Japan, in measurements of muon decay properties in the MEGA and RHO experiments at the LAMPF accelerator, in a detailed analysis of scattering effects in the purported observation of a 17 keV neutrino at Oxford, in a search for a disoriented chiral condensate with the MiniMax experiment at Fermilab, and in an R&D program on resistive plate counters that could find use in low-cost high-quality charged particle detection at low rates
The ABC Effect in Double-Pionic Nuclear Fusion and a pn Resonance as its Possible Origin
The ABC effect -- a long-standing puzzle in double-pionic fusion -- has been
reexamined by the first exclusive and kinematically complete measurements of
solid statistics for the fusion reactions , He and He using the WASA detector, first at
CELSIUS and recently at COSY -- the latter with a statistics increased by
another two orders of magnitude. In all cases we observe a huge low-mass
enhancement in the -invariant mass accompanied by a pronounced
excitation. For the most basic fusion reaction, the reaction, we observe in addition a very pronounced resonance-like
energy dependence in the total cross section with a maximum 90 MeV below the
mass and a width of only 50 MeV, which is five times smaller
than expected from a conventional -channel excitation. This
reveals the ABC effect to be the consequence of a s-channel resonance with the
formfactor of this dibaryonic state being reflected in the low-mass enhancement
of the -invariant mass. From the fusion reactions to He and He
we learn that this resonance is robust enough to survive even in nuclei.Comment: conference proceedings PANIC 0
Elemental Analysis of Glass and Bakelite Electrodes Using PIXE Facility
The evolution of particle detectors dates back to the discovery of X-rays and
radioactivity in 1890s. In detector history, the Resistive Plate Chambers
(RPCs) are introduced in early 1980s. An RPC is a gaseous detector made up of
two parallel electrodes having high resistivity like that of glass and
bakelite. Currently several high energy physics experiments are using RPC-based
detector system due to robustness and simplicity of construction. In each and
every experiment, RPCs have to run continuously for several years. So, it
demands an in-depth characterization of the electrode materials. In the present
study, an elemental analysis of locally available glass and bakelite samples is
done using PIXE facility available at Panjab University Cyclotron, Chandigarh.
PIXE measurements are done using 2.7 MeV proton beam incident on the electrode
sample target. The constituent elements present in these electrode samples are
reported.Comment: 4 pages, 1 figures, 1 table; Presented in XXII DAE-BRNS High Energy
Physics Symposium 201
CP Tagged Decays at SuperBaBar
We explore the possibility of measuring the CKM parameter gamma using CP
tagged decays at a very high luminosity e+e- B Factory. A new collider capable
of integrating as much as 10 inverse attobarns per year is being discussed as a
possible future for SLAC beyond the current PEP-II program, and could also be
in the future of KEK. In two years of operation, it could be possible for a
successor to BaBar or Belle to accumulate a sample of one million CP tagged B
decays. We find that a theoretically clean extraction of gamma with uncertainty
less than 5 degrees may be achievable in the analysis of such a data set.Comment: 14 pages, 4 figures; minimal revisions for version to appear in
Physical Review D, all formulas and conclusions unchange
Search for neutrinoless tau decays tau -> 3l and tau -> l K0S
Neutrinoless tau-lepton decays into either three leptons (tau- -> l1- l2 l3)
or one lepton and one K0S meson(tau- -> l- K0S) where lepton l means either an
electron or muon, have been searched for using 48.6 fb^{-1} of data collected
with the Belle detector at the KEKB e+e- collider. No evidence for candidate
decays are found in any channel. Therefore we set 90% confidence level upper
limits on the branching fraction for 8 different decay modes. These limits are
more stringent than those set previously and reach to the 10^{-7} level.Comment: Invited talk at the Seventh International Workshop on Tau Lepton
Physics (TAU02), Santa Cruz, Ca, USA, Sept 2002, 7 pages, LaTeX, 3 eps
figure
Eta-Helium Quasi-Bound States
The cross section and tensor analysing power t_20 of the d\vec{d}->eta 4He
reaction have been measured at six c.m. momenta, 10 < p(eta) < 90 MeV/c. The
threshold value of t_20 is consistent with 1/\sqrt{2}, which follows from
parity conservation and Bose symmetry. The much slower momentum variation
observed for the reaction amplitude, as compared to that for the analogous
pd->eta 3He case, suggests strongly the existence of a quasi-bound state in the
eta-4He system and optical model fits indicate that this probably also the case
for eta-3He.Comment: LaTeX, uses elsart.sty, 10 pages, 3 Postscript figures, Submitted to
Physics Letters
Test of Factorization Hypothesis from Exclusive Non-leptonic B decays
We investigate the possibility of testing factorization hypothesis in
non-leptonic exclusive decays of B-meson. In particular, we considered the non
factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+}
(\pi^-, \rho^-) known as well-factorizable modes. By taking the ratios
BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(\pi^-,\rho^-)), we
found that under the present theoretical and experimental uncertainties there's
no evidence for the breakdown of factorization description to heavy-heavy
decays of the B meson.Comment: 11 pages; submitted to PR
New physics effects to the lepton polarizations in the B -> K l^+ l^- decay
Using the general, model independent form of the effective Hamiltonian, the
general expressions of the longitudinal, normal and transversal polarization
asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B
-> K l^+ l^-) decay are found. The sensitivity of lepton polarizations and
their combinations on new Wilson coefficients are studied. It is found that
there exist regions of Wilson coefficients for which the branching ratio
coincides with the Standard Model result while the lepton polarizations differ
substantially from the standard model prediction. Hence, studying lepton
polarization in these regions of new Wilson coefficients can serve as a
promising tool for establishing new physics beyond the Standard Model.Comment: 18 pp, 14 figures (postscript formatted), LaTex formatte
CP Violation in Kaon System in Supersymmetric SU(5) Model with Seesaw-Induced Neutrino Masses
CP violations in the kaon system are studied in supersymmetric SU(5) model
with right-handed neutrinos. We pay a special attention to the renormalization
group effect on the off-diagonal elements of the squark mass matrices. In
particular, if the Yukawa couplings and mixings in the neutrino sector are
sizable, off-diagonal elements of the right-handed down-type squark mass matrix
are generated, which affect CP and flavor violations in decay processes of the
kaon. We calculate supersymmetric contributions to epsilon (as well as Delta
m_K), Br(K_L -> pi^0 nu \bar{nu}), and epsilon'/epsilon in this framework. We
will see that the supersymmetric contribution to the epsilon parameter can be
as large as (and in some case, larger than) the experimentally measured value.
We also discuss its implication to future tests of the unitarity triangle of
the Kobayashi-Maskawa matrix.Comment: 30 pages, 5 figue
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