32 research outputs found
Transition radiation induced by nonrelativistic electron bunches
The experiments showed that the Bernstein β Green β Kruskal (BGK)-waves can be used to form short electron bunches
with time durations ranging between 50 and 100 ps. Experiments on generating electromagnetic pulses (EMPs) by
using nonrelativistic electron bunches passing through diaphragms of various radii and complex geometries are
described. Results obtained may also be used in designing devices for generating EMPs with tunable characteristics.Π ΠΎΠ·Π³Π»ΡΠ΄Π°ΡΡΡΡΡ ΠΌΠΎΠΆΠ»ΠΈΠ²ΡΡΡΡ Π³Π΅Π½Π΅ΡΠ°ΡΡΡ ΠΊΠΎΡΠΎΡΠΊΠΈΡ
Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΈΡ
Π·Π³ΡΡΡΠΊΡΠ² ΡΡΠΈΠ²Π°Π»ΡΡΡΡ Π²ΡΠ΄ 50 Π΄ΠΎ 100 ΠΏΡ Ρ
Π²ΠΈΠ»ΡΠΌΠΈ
ΠΠ΅ΡΠ½ΡΡΠ΅ΠΉΠ½Π°-ΠΡΡΠ½Π°-ΠΡΡΡΠΊΠ°Π»Π° (ΠΠΠ) Ρ ΡΠΎΡΠΌΡΠ²Π°Π½Π½Ρ Π΅Π»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΡΡΠ½ΠΈΡ
ΡΠΌΠΏΡΠ»ΡΡΡΠ² (ΠΠΠ) Π· ΠΊΠ΅ΡΠΎΠ²Π°Π½ΠΈΠΌΠΈ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ Π½Π° Π΄ΡΠ°ΡΡΠ°Π³ΠΌΠ°Ρ
ΡΡΠ·Π½ΠΎΡ Π³Π΅ΠΎΠΌΠ΅ΡΡΡΡ. ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠΈ ΠΏΡΠΎΠ΄Π΅ΠΌΠΎΠ½ΡΡΡΡΠ²Π°Π»ΠΈ, ΡΠΎ ΠΠΠ-Ρ
Π²ΠΈΠ»Ρ ΠΌΠΎΠΆΡΡΡ Π±ΡΡΠΈ
Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Ρ Π΄Π»Ρ ΡΠΎΡΠΌΡΠ²Π°Π½Π½Ρ ΠΊΠΎΡΠΎΡΠΊΠΈΡ
Π΅Π»Π΅ΠΊΡΡΠΎΠ½Π½ΠΈΡ
Π·Π³ΡΡΡΠΊΡΠ² Π· ΠΊΠ΅ΡΠΎΠ²Π°Π½ΠΈΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ.Π Π°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°Π΅ΡΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ Π³Π΅Π½Π΅ΡΠ°ΡΠΈΠΈ ΠΊΠΎΡΠΎΡΠΊΠΈΡ
ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΡ
ΡΠ³ΡΡΡΠΊΠΎΠ² ΠΏΡΠΎΡΡΠΆΠ΅Π½Π½ΠΎΡΡΡΡ ΠΎΡ 50 Π΄ΠΎ 100 ΠΏΡ
Π²ΠΎΠ»Π½Π°ΠΌΠΈ ΠΠ΅ΡΠ½ΡΡΠ΅ΠΉΠ½Π°-ΠΡΠΈΠ½Π°-ΠΡΡΡΠΊΠ°Π»Π° (ΠΠΠ) ΠΈ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΡΡ
ΠΈΠΌΠΏΡΠ»ΡΡΠΎΠ² (ΠΠΠ) Ρ
ΡΠΏΡΠ°Π²Π»ΡΠ΅ΠΌΡΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ Π½Π° Π΄ΠΈΠ°ΡΡΠ°Π³ΠΌΠ°Ρ
ΡΠ°Π·Π½ΡΡ
Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΠΉ. ΠΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΡ ΠΏΡΠΎΠ΄Π΅ΠΌΠΎΠ½ΡΡΡΠΈΡΠΎΠ²Π°Π»ΠΈ, ΡΡΠΎ
ΠΠΠ-Π²ΠΎΠ»Π½Ρ ΠΌΠΎΠ³ΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡΡΡ Π΄Π»Ρ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΊΠΎΡΠΎΡΠΊΠΈΡ
ΠΠΠ Ρ ΡΠΏΡΠ°Π²Π»ΡΠ΅ΠΌΡΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ
On the analysis of the pi -> e nu gamma experimental data
The most general amplitude for the radiative pion decay pi -> e nu gamma
including terms beyond V-A theory is considered. The experimental constraints
on the decay amplitude components are discussed. A model independent
presentation of the results of high statistics and high resolution experiments
is suggested.Comment: 5 pages, 2 figure
Radiative corrections to radiative \pi e 2 decay
The lowest order radiative corrections (RC) to width and spectra of radiative
decay are calculated. We take into account virtual photon emission
contribution as well as soft and hard real photon emission one. The result
turns out to be consistent with the standard Drell-Yan picture for the width
and spectra in the leading logarithmical approximation which permits us to
generalize it to all orders of perturbation theory. Explicit expressions of
nonleading contributions are obtained. The contribution of short distance is
found to be in agreement with Standard Model predictions. It is presented as a
general normalization factor. We check the validity of the
Kinoshita-Lee-Nauenberg theorem about cancellation in the total width of the
mass singularities at zero limit of electron mass. We discuss the results of
the previous papers devoted to this problem. The Dalitz plot distribution is
illustrated numerically.Comment: 21 pages, 3 figures, 3 tables; a table with K-factor values was adde
and Polarizabilities from {} Data on the Base of S-Matrix Approach
We suggest the most model-independent and simple description of the
process near threshold in framework of S-matrix
approach. The amplitudes contain the pion polarizabilities and rather
restricted information about interaction. Application of these
formulae for description of MARK-II \cite{M2} and Crystal Ball \cite{CB} data
gives: ,
(in units system ) at the experimental values of scattering lengths. Both
values are compartible with current algebra predictions.Comment: LaTeX, 14 pages plus 6 figures (not included, available upon request)
, ISU-IAP.Th93-03, Irkuts
Measurement of the Dalitz plot slope parameters for K- -> pi0 pi0 pi- decay using ISTRA+ detector
The Dalitz plot slope parameters g, h and k for the K- -> pi0 pi0 pi- decay
have been measured using in-flight decays detected with the ISTRA+ setup
operating in the 25 GeV negative secondary beam of the U-70 PS. About 252 K
events with four-momenta measured for the pi- and four involved photons were
used for the analysis. The values obtained g=0.627+/-0.004(stat)+/-0.010(syst),
h=0.046+/-0.004(stat)+/-0.012(syst), k=0.001+/-0.001(stat)+/-0.002(syst) are
consistent with the world averages dominated by K+ data, but have significantly
smaller errors.Comment: LaTeX, 10 pages, 8 eps-figures, update of IHEP 2002-1
T-Odd Correlations in pi->e nu_e gamma and pi->mu nu_mu gamma Decays
The transverse lepton polarization asymmetry in pi_l2gamma decays may probe
T-violating interactions beyond the Standard Model. Dalitz plot distributions
of the expected effects are presented and compared to the contribution from the
Standard Model final state interactions. We give an example of a
phenomenologically viable model, where a considerable contribution to the
transverse lepton polarization asymmetry arises.Comment: 19 pages, 5 figures. To be published in Phys.Rev.D. Fixed sign in FSI
contribution figure, fixed formulas in K-bar{K} mixing analysis, added some
minor comment
Extraction of Kaon Formfactors from K^- -> mu^- nu_mu gamma Decay at ISTRA+ Setup
The radiative decay K->mu nu gamma has been studied at ISTRA+ setup in a new
kinematical region. About 22K events of K^- -> mu^- nu_mu gamma have been
observed. The sign and value of Fv-Fa have been measured for the first time.
The result is Fv-Fa=0.21(4)(4).Comment: 11 pages, 21 figures, submitted to Phys. Lett.
Search for light pseudoscalar sgoldstino in K- decays
A search for the light pseudoscalar sgoldstino production in the three body
K- decay K-->pipi0P has been performed with the ISTRA+ detector exposed to the
25 GeV negative secondary beam of the U70 proton synchrotron. No signal is
seen. An upper limit for the branching ratio Br(K->pipi0P), at 90% confidence
level, is found to be around 9*10**-6 in the effective mass m(P) range from 0
till 200 MeV, excluding the region near m(pi0) where it degrades to 3.5*10**-5.Comment: 10 pages, LATEX, 8 EPS figures, revised version, to be published in
Phys.Lett.
High statistic measurement of the K- -> pi0 e- nu decay form-factors
The decay K- -> pi0 e- nu is studied using in-flight decays detected with the
ISTRA+ spectrometer. About 920K events are collected for the analysis. The
lambda+ slope parameter of the decay form-factor f+(t) in the linear
approximation (average slope) is measured: lambda+(lin)= 0.02774 +-
0.00047(stat) +- 0.00032(syst). The quadratic contribution to the form-factor
was estimated to be lambda'+ = 0.00084 +- 0.00027(stat) +- 0.00031(syst). The
linear slope, which has a meaning of df+(t)/dt|_{t=0} for this fit, is lambda+
= 0.02324 +- 0.00152(stat) +- 0.00032(syst). The limits on possible tensor and
scalar couplings are derived: f_{T}/f_{+}(0)=-0.012 +- 0.021(stat) +-
0.011$(syst), f_{S}/f_{+}(0)=-0.0037^{+0.0066}_{-0.0056}(stat) +- 0.0041(syst).Comment: 11 pages, 8 figures. Accepted by Phys.Lett.
Search for Heavy Neutrino in K->mu nu_h(nu_h-> nu gamma) Decay at ISTRA+ Setup
Heavy neutrino nu_h with m_h < 300MeV/c^2 can be effectively searched for in
kaon decays. We put upper limits on mixing matrix element |U_mu_h}|^2 for
radiatively decaying nu_h from K->mu nu_h (nu_h -> nu gamma) decay chain in the
following parameter region: 30MeV/c^2 < m_h < 80MeV/c^2; 10^{-11}sec < tau_h <
10^{-9}sec. For the whole region |U_{mu h}|^2 < 5 x 10^{-5} for Majorana type
of nu_h and | U_{\mu h}|^2 < 8 x 10^{-5} for the Dirac case.Comment: Published in Phys. Lett.