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1.
We discuss here the binary reactions of strange and charmed particle production in
collisions at intermediate energies. In the case of baryon production with only one strange or charmed quark the cross section is determined by planar diagrams withK
*,K
** orD
*,D
**-meson poles in thet-channel. We calculated these diagrams in the frame of quark-gluon string model (QGSM) proposed earlier. We obtained also the cross-sections for reactions with baryon exchange in thet-channel with
and
pair in the final state. Predicted cross-sections for the reactions of
production are of the order of hundred nanobarns. Using reggeon calculus we estimated cross-sections of binary reactions with two or three strange quarks in the final state:
and . We discuss also the possible manifestation of color transparency effects in reactions with antiprotons on nuclei where all antiproton quarks annihilate. 相似文献
2.
Kiselev V. V. Likhoded A. K. Shevlyagin M. V. 《Zeitschrift fur Physik C Particles and Fields》1994,63(1):77-86
The cross-section for the production of
quarks ine
+
e
– annihilation, that proves to be at a level of
for
is calculated within the frames of the QCD perturbation theory. The cross sections for the associated production of 1S-and 2S-wave states ofB
c-meson in the reaction
were calculated in the nonrelativistic model of a heavy quarkonium. The number of
bc
-hyperons to be expected at LEP is estimated on the basis of the assumption on quark-hadron duality. 相似文献
3.
G. T. Jones R. W. L. Jones B. W. Kennedy S. W. O'Neale O. Villalobos-Baillie H. Klein D. R. O. Morrison P. Schmid H. Wachsmuth D. B. Miller M. M. Mobayyen S. Wainstein M. Aderholz D. Hantke U. F. Katz J. Kern N. Schmitz W. Wittek H. P. Borner G. Myatt D. Radojicic F. W. Bullock S. Burke 《Zeitschrift fur Physik C Particles and Fields》1993,57(2):197-209
The production of the neutral strange particlesK
0, and
invp and
charged current interactions is studied in an experiment with the Big European Bubble Chamber. Mean multiplicities are measured as a function of the event variablesE
v,W
2 andQ
2 and of the hadron variablesx
F,z andp
T
2
.K
*± (892) and
*± (1385) signals are observed, whereas there is no evidence for
*- (1385) production invp scattering. Forward, backward and total mean multiplicities are found to compare well with the predictions of an empirical model for deep-inelastic reactions in the case of the strange mesonsK
0 andK
*± (892) but less so for the strange baryons ,
and
*± (1385). The strange baryon multiplicities are used to obtain the decuplet to octet baryon production ratio and to assess the probabilities of auu orud system to break up. 相似文献
4.
5.
P. Weidenauer K. D. Duch H. Kalinowsky E. Klempt B. May J. Reifenröther C. Straßburger U. Gastaldi R. Landua W. Dahme J. C. Bizot B. Delcourt B. L. White C. Amsler M. Doser J. Riedlberger U. Straumann P. Truöl 《Zeitschrift fur Physik C Particles and Fields》1993,59(3):387-398
annihilation at rest into five pions was studied in the ASTERIX spectrometer by stopping antiprotrons from LEAR in a H2 or D2 gas target. In
annihilations in H2 leading to the +–+–0 final state, the invariant mass spectra of two, three, and four pions show no evidence for any new narrow states. In
the difference of the four pion mass spectra recoiling against a – and those recoiling against a + shows a resonance-like structure ( (1480)), confirming a previous analysis with a smaller event sample. The (1480) mass is shown to depend strongly on the momentum of the spectator proton. In H2, we searched for the (1480) in the reaction
(1480), (1480) +–+– to clarify whether the (1480) is identical to the 4-mode of thef
2 (1520). No evidence for this decay mode was found. A prominent resonance in
innihilation into five pions is the meson. We find two quasi-two-body intermediate states:
and
(1235). The mass and width of theb
1 (1235) are determined to be:
相似文献
6.
In the reactione
+
e
– W
+
W
– (
) (
) we expect that normally the colour singlet systems (
) and (
) hadronize independently into two hadron chains or strings. However also the pairs (
) and (
) form colour singlets with probability 1/N
c
2
=1/9. This probability could be further enhanced by gluon exchange. We therefore expect that the hadronization can give recoupled colour strings between these quark-antiquark pairs with some small probability, and a study of this effect will give interesting information about the vacuum structure. In this paper we discuss a possible experimental signal for recoupled events and show that such events can be identified also when the effect of gluon emission before the recoupling is taken into account. 相似文献
7.
Daniel Froidevaux Elżbieta Richter-Was 《Zeitschrift fur Physik C Particles and Fields》1995,67(2):213-225
A detailed study of associated Standard Model Higgs production (WH and
) at the LHC (or a possible upgraded Tevatron collider), where the Higgs boson decays to
pairs, is reported for 80m
H
<120 gev.=" even=" for=">120>b-tagging performances of the detector, the signal cannot be cleanly extracted from the background. For an integrated luminosity of 104
pb
–1 andm
H
=100 GeV, one can expect at best 110 reconstructed
decays fromWH production, above a resonant background of 150WZ events and a non-resonant background of 4800 events, and 100 reconstructed
pairs (of which 50 from
decay) from
production, above a background of 4000 events. The main difficulty in extracting these two channels is in the expected low signal rate after reconstruction, the need for accurate control of all the background sources and for extremely goodb-tagging performance. Nevertheless, for a few years of running at a luminosity of 1033 cm–2s–1,
channel may be the best way to probe the region 80m
H
<100>100> 相似文献
8.
An extension of the Supersymmetric Standard Model to the supersymmetricSU(2)
L×SU(2)
R×U(1)
B–L model is considered. The gauge group contains a bidoublet and triplet Higgs field. We investigate the possibility of detecting chargino and neutralino production in
-collisions atCDF, namely
. A numerical analysis is performed for
, tan 1 and a lower bound on the lightest supersymmetric particle (LSP) mass,
GeV. Using conservative assumptions ofM
WR300 GeV andgg
Lg
R, we find the cross sections are:
, and
pb, and thus
L
24
L
at
TeV. Cross sections are also given for larger values of the center of mass energy
up to those available at the SSC. The results are compared with the prompt-lepton background of theW
L, R
–
decays from
. Both decays for
bosons show Jacobian peaks for
(p
T150 GeV forM
WR) at =90°. Furthermore the chargino signature unlike the promptlepton background is symmetric under the Jacobian peak. We also exhibit the dependence of the angular distribution of the chargino on the c.m. angle forp
T40 GeV, 150 GeV at
TeV. 相似文献
9.
Blinov A. E. Blinov V. E. Bondar A. E. Bukin A. D. Groshev V. R. Klimenko S. G. Onuchin A. P. Panin V. S. Protopopov I. Ya. Shamov A. G. Sidorov V. A. Skovpen Yu. I. Skrinsky A. N. Tayursky V. A. Telnov V. I. Tikhonov Yu. A. Tumaikin G. M. Undrus A. E. Vorobiov A. I. Zhilich V. N. 《Zeitschrift fur Physik C Particles and Fields》1994,62(3):367-370
Using the MD-1 detector at the VEPP-4e
+
e
– strorage ring we have measured the inclusive and370-1 production rates in direct (1S) decays
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