34 research outputs found
Study of electron beam energy conversion at gyrocon–linear accelerator facility
A gyrocon together with the high-voltage 1.5 MeV accelerator ELIT-3A represents a power generator at 430 MHz
serving for linear electron accelerator pulse driving. The facility description and results of calorimetric measurements of
ELIT-3A electron beam power and accelerated beam at the end of accelerator are presented in the paper. The achieved
energy conversion efficiency is about 55%.Гирокон разом з високовольтним 1.5 МеВ прискорювачем ЕЛІТ-3А являє собою генератор потужності
на частоті 430 МГц і служить для збудження лінійного прискорювача електронів в імпульсному режимі.
Приведено опис установки і результати калориметричних вимірів потужності електронного пучка ЕЛІТ-3А і
прискореного пучку на виході лінійного прискорювача. Отриманий КПД перетворення 55%.Гирокон совместно с высоковольтным 1.5 МэВ ускорителем ЭЛИТ-3А представляет собой генератор
мощности на частоте 430 МГц и служит для возбуждения линейного ускорителя электронов в импульсном
режиме. Приведено описание установки и результаты калориметрических измерений мощности электронного пучка ЭЛИТ-3А и ускоренного пучка на выходе линейного ускорителя. Получен КПД преобразования
55%
Industrial high power electron accelerator for the energy 5-10 MeV
This paper presents the project of an industrial accelerator of the modular structure. Accelerating structure consists of the chain of coaxial ILU cavities, connected by the coupling cavities. Two designs of accelerating structure, differing by a version of coupling cavities, are presented. Main parameters of the accelerator are: energy of electrons 5-10 MeV, average beam power up to 150 kW, operating frequency 176 MHz, duty factor 10%
Magnetic moments of antidecuplet pentaquarks
We analyze the magnetic moment of the exotic pentaquarks of the flavor
antidecuplet in the constituent quark model for the case in which the ground
state is in an orbital L(p)=0(+) or a L(p)=1(-) state. We derive sum rules for
the magnetic moments. The magnetic moment of the Theta(1540) is found to be
0.38, 0.09 and 1.05 mu_N for J(p)=1/2(-), 1/2(+) and 3/2(+), respectively,
which is compared with the results obtained in other approaches.Comment: 15 pages, 1 figure, 3 tables. Revised version, extended introduction
and discussion, accepted for publication in Physics Letters
5 MeV 300 kW electron accelerator project
The paper presents a project of a high power linear accelerator for industrial applications. The accelerator has a modular structure and consists of the chain of accelerating cavities connected by the axis-located coupling cavities with coupling slots in the common walls. Main parameters of the accelerator are: operating frequency of 176 MHz, electron energy
ofup to 5 MeV, average beam power of300 kW. The required RF pulse power can be supplied by the TH628 diacrode.Розглянуто проект промислового електронного прискорювача великої потужності. Прискорювач має модульну
прискорюючу структуру, що складається з ланцюжка резонаторів, зв'язаних за допомогою аксиально-розміщених
резонаторів зв'язку. Зв'язок здійснюється щілинами в загальних стінках. Основні параметри прискорювача: робоча
частота 176 МГц, енергія електронів 5 МеВ, середня потужність пучка до 300 кВт. Необхідна високочастотна імпульсна потужність може бути отримана, наприклад, від діакрода TH628.Рассмотрен проект промышленного электронного ускорителя большой мощности. Ускоритель имеет модульную
ускоряющую структуру, состоящую из цепочки ускоряющих резонаторов, связанных посредством аксиально-расположенных резонаторов связи. Связь осуществляется щелями в общих стенках. Основные параметры ускорителя: рабочая
частота 176 МГц, энергия электронов 5 МэВ, средняя мощность пучка до 300 кВт. Необходимая высокочастотная импульсная мощность может быть получена, например, от диакрода TH628
Search for a strongly decaying neutral charmed pentaquark
We present a search for a charmed pentaquark decaying strongly to
. Finding no evidence for such a state, we set limits on the cross
section times branching ratio relative to and under particular
assumptions about the production mechanism.Comment: To be published in Physics Letters
Study of the q^2-Dependence of B --> pi ell nu and B --> rho(omega)ell nu Decay and Extraction of |V_ub|
We report on determinations of |Vub| resulting from studies of the branching
fraction and q^2 distributions in exclusive semileptonic B decays that proceed
via the b->u transition. Our data set consists of the 9.7x10^6 BBbar meson
pairs collected at the Y(4S) resonance with the CLEO II detector. We measure
B(B0 -> pi- l+ nu) = (1.33 +- 0.18 +- 0.11 +- 0.01 +- 0.07)x10^{-4} and B(B0 ->
rho- l+ nu) = (2.17 +- 0.34 +0.47/-0.54 +- 0.41 +- 0.01)x10^{-4}, where the
errors are statistical, experimental systematic, systematic due to residual
form-factor uncertainties in the signal, and systematic due to residual
form-factor uncertainties in the cross-feed modes, respectively. We also find
B(B+ -> eta l+ nu) = (0.84 +- 0.31 +- 0.16 +- 0.09)x10^{-4}, consistent with
what is expected from the B -> pi l nu mode and quark model symmetries. We
extract |Vub| using Light-Cone Sum Rules (LCSR) for 0<= q^2<16 GeV^2 and
Lattice QCD (LQCD) for 16 GeV^2 <= q^2 < q^2_max. Combining both intervals
yields |Vub| = (3.24 +- 0.22 +- 0.13 +0.55/-0.39 +- 0.09)x10^{-3}$ for pi l nu,
and |Vub| = (3.00 +- 0.21 +0.29/-0.35 +0.49/-0.38 +-0.28)x10^{-3} for rho l nu,
where the errors are statistical, experimental systematic, theoretical, and
signal form-factor shape, respectively. Our combined value from both decay
modes is |Vub| = (3.17 +- 0.17 +0.16/-0.17 +0.53/-0.39 +-0.03)x10^{-3}.Comment: 45 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance
We have made a first measurement of the lepton momentum spectrum in a sample
of events enriched in neutral B's through a partial reconstruction of B0 -->
D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the
Upsilon(4S) resonance by the CLEO II detector, is compared directly to the
inclusive lepton spectrum from all Upsilon(4S) events in the same data set.
These two spectra are consistent with having the same shape above 1.5 GeV/c.
From the two spectra and two other CLEO measurements, we obtain the B0 and B+
semileptonic branching fractions, b0 and b+, their ratio, and the production
ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950
(+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57
+- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes,
tau+/tau0.Comment: 14 page, postscript file also available at
http://w4.lns.cornell.edu/public/CLN
Search for CP Violation in D^0--> K_S^0 pi^+pi^-
We report on a search for CP violation in the decay of D0 and D0B to Kshort
pi+pi-. The data come from an integrated luminosity of 9.0 1/fb of e+e-
collisions at sqrt(s) ~ 10 GeV recorded with the CLEO II.V detector. The
resonance substructure of this decay is well described by ten quasi-two-body
decay channels (K*-pi+, K*0(1430)-pi+, K*2(1430)-pi+, K*(1680)-pi+, Kshort rho,
Kshort omega, Kshort f0(980), Kshort f2(1270), Kshort f0(1370), and the ``wrong
sign'' K*+ pi-) plus a small non-resonant component. We observe no evidence for
CP violation in the amplitudes and phases that describe the decay D0 to K_S^0
pi+pi-.Comment: 10 pages, 3 figures, also available at
http://w4.lns.cornell.edu/public/CLNS/, submitted to PR
Measurement of Lepton Momentum Moments in the Decay bar{B} \to X \ell \bar{\nu} and Determination of Heavy Quark Expansion Parameters and |V_cb|
We measure the primary lepton momentum spectrum in B-bar to X l nu decays,
for p_l > 1.5 GeV/c in the B rest frame. From this, we calculate various
moments of the spectrum. In particular, we find R_0 = [int(E_l>1.7)
(dGam/dE_sl)*dE_l] / [int(E_l>1.5) (dGam/dE_sl)*dE_l] = 0.6187 +/- 0.0014_stat
+/- 0.0016_sys and R_1 = [int(E_l>1.5) E_l(dGam/dE_sl)*dE_l] / [int(E_l>1.5)
(dGam/dE_sl)*dE_l] = (1.7810 +/- 0.0007_stat +/- 0.0009_sys) GeV. We use these
moments to determine non-perturbative parameters governing the semileptonic
width. In particular, we extract the Heavy Quark Expansion parameters
Lambda-bar = (0.39 +/- 0.03_stat +/- 0.06_sys +/- 0.12_th) GeV and lambda_1 =
(-0.25 +/- 0.02_stat +/- 0.05_sys +/- 0.14_th) GeV^2. The theoretical
constraints used are evaluated through order 1/M_B^3 in the non-perturbative
expansion and beta_0*alpha__s^2 in the perturbative expansion. We use these
parameters to extract |V_cb| from the world average of the semileptonic width
and find |V_cb| = (40.8 +/- 0.5_Gam-sl +/- 0.4_(lambda_1,Lambda-bar)-exp +/-
0.9_th) x 10^-3. In addition, we extract the short range b-quark mass m_b^1S =
(4.82 +/- 0.07_exp +/- 0.11_th) GeV/c^2. Finally, we discuss the implications
of our measurements for the theoretical understanding of inclusive semileptonic
processes.Comment: 21 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Measurement of the Mass Splittings between the States
We present new measurements of photon energies and branching fractions for
the radiative transitions: Upsilon(2S)->gamma+chi_b(J=0,1,2). The masses of the
chi_b states are determined from the measured radiative photon energies. The
ratio of mass splittings between the chi_b substates,
r==(M[J=2]-M[J=1])/(M[J=1]-M[J=0]) with M the chi_b mass, provides information
on the nature of the bbbar confining potential. We find
r(1P)=0.54+/-0.02+/-0.02. This value is in conflict with the previous world
average, but more consistent with the theoretical expectation that r(1P)<r(2P);
i.e., that this mass splittings ratio is smaller for the chi_b(1P) triplet than
for the chi_b(2P) triplet.Comment: 11 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN