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1.
We consider the Schrödinger operatorH = – +V(|x|) onR
3. Letn
denote the number of bound states with angular momentum (not counting the 2 + 1 degeneracy). We prove the following bounds onn
. LetV 0 and d/dr r
1-2p
(-V)1 –p
0 for somep [1/2, 1) then
相似文献
2.
We examine the prospects for observing weak flavour-changing neutral current (FCNC) decays ofB mesons at hadron colliders, including effects of anomalousWWZ vertices. Since it is very difficult to measure the inclusive rate B Xs +– one should consider exclusive modes such as BK* + – and B K+ –. Even though this requires one to compute hadronic matrix elements, we show that experimentally observable quantities (ratios of decay rates) are not strongly parametrisation dependent. Some possibilities for reducing the theoretical uncertainties from other experimental data are discussed. 相似文献
3.
We parametrise the polarised gluon and sea distribution functions incorporating the interpretation of the EMC experiment that, due to the axial anomaly the observed quark contribution to proton spin
at Q
2>=10.7 GeV2. Typical processes to isolate the gluonic and sea content of the proton studied here are the largeP
T
direct photon production processes (a) using single polarized protonPPX and (b) polarized beam and target protonPPX. In both the above process the dominant contribution comes from the Compton subprocess and so can be used as a clean probe of the gluonic content of the proton. LargeP
T
muon pair production PP(+–)X are also studied and we find that the annihilation subprocess dominates, but not much larger than the Compton subprocess and so may not be a clean probe of the sea content of the proton. The effect of two loop corrections to the parametrisation and asymmetries are also considered, and are found to be negligible. 相似文献
4.
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
5.
Nils A. Törnqvist 《Zeitschrift fur Physik C Particles and Fields》1994,61(3):525-537
A systematic study of possible deuteronlike twomeson bound states,deusons, is presented. Previous arguments that many such bound states may exist are elaborated with detailed arguments and numerical calculations including, in particular, the tensor potential. This tensor potential which is crucial for the deuteron binding is shown to be very important also in the mesonic case. Especially, in the pseudoscalar3
P
0 pseudoscalar-vector
and vector-vector
channels the important observation is made that the centrifugal barrier from theP-wave can be overcome by the 1/r
2 and 1/r
3 terms of the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteronlike
and
composites bound by approximately 50 MeV. Composites of
and
states bound by pion exchange alone are expected near the thresholds, while in the light meson sector one generally needs some additional short range attraction to form bound states. The quantum numbers of these states areI=0, andJ
PC=0–+, 1++ for the
states andI=0,J
PC=0++, O–+, 1+– and 2++ for the
composites. In
the states:
b
(10545),
b1(10562) are predicted and in
, one finds the states:
b
(10590),
bQ
(10582),h
b(10608),
b2(10602). Near the
threshold the states:
c
(3870),
c0(3870) are predicted, and near the
threshold one finds the states:
b0(4015),
c
(4015),h
c(4015),
c2(4015). Within the light meson sector pion exchange gives strong attraction for
and
systems with quantum numbers where the best non-
candidates exist, although pion exchange alone is not strong enough to support such bound states. Thus, although one cannot conclude with certainty it to be the case, this fact does favour the picture that the (1440) and thef
1 (1420) are mainly
composites and thef
0(1710) mainly a
bound state, while thef
0(1515) andf
2(1520) could be predominantly
composites. If the predicted
and
states are found, these would support this interpretation of the light states. In channels with exotic flavour orCP quantum numbers pion exchange is generally repulsive or quite weak. Therefore one does not expect that such deuteronlike bound states exist, althoughB*B* may be an exception. 相似文献
6.
R. G. Badalyan 《Zeitschrift fur Physik C Particles and Fields》1992,55(4):647-651
The mechanism of fast-hadron leptoproduction in nuclei in deep inelastic region is considered. Different possible mechansims of fast-hadron formation in the virtual-photon fragmentation region and the process of transition of the quark (quark-gluon system) through nuclear matter is analysed. The range of consistency of the SLAC and EMC CERN data on meson leptoproduction in different nuclei is obtained to be 0.2 GeV2m
c
2
0.5 GeV2. It is shown that the kinematic region 0.05x
B
0.3 and (3–5)Q
2/m
c
2
100 is the most favourable for an investigation of the growth law (evolution) of the transverse dimensions of quark (quark-gluon system) produced by the virtual photon. 相似文献
7.
A. V. Bannikov J. Bohm W. Dominik Ya. V. Grishkevich T. Gemesy A. K. Javrishvili L. Jenik A. I. Kharchilava J. Krasznovszky Z. V. Krumstein V. Krysteva T. A. Lomtadze Yu. P. Merekov S. Nedev V. N. Penev V. I. Petrukhin Gy. Pinter K. Piška K. Šafařik G. A. Shelkov A. I. Shklovskaja Š. Valkár L. S. Vertogradov P. Závada 《Zeitschrift fur Physik C Particles and Fields》1991,49(2):245-249
The –
p interactions with at least one charged secondary produced at polar angle 90° in c.m.s. and having the transverse momentum above 1 GeV/c were investigated. The data were obtained using streamer chamber magnetic spectrometer RISK at 38 GeV/c beam from Serpukhov accelerator. The analyzis of associated production in reconstructed events suggests, that if the transverse momentum of a pair of oppositely charged secondaries compensates the trigger particlep
practically completely, this pair is the product of the 0 decay in marked fraction of such events. We observed a large spin-alignment for the 0-mesons selected as described above: the probability of zero spin projection onto the normal to the 0 production plane is equal to
00
T
=0.86±0.23. The enhancement of the number of events, in which the 0 picks up practically full momentum transfer carrying by the exchange, and also the enlarged tensor polarization for the 0-mesons in these events could be qualitatively explained as manifestation of direct 0-production via the QCD higher twist processes in the highp
–
p collisions. At the same time, the observed effects are markedly larger than the values predicted with QCD model in which the higher twist corrections were included. 相似文献
8.
9.
W. Bernreuther G. W. Botz O. Nachtmann P. Overmann 《Zeitschrift fur Physik C Particles and Fields》1991,52(4):567-573
We calculate CP-odd correlations inZ decays to leptons,
. These correlations are sensitive to the weak dipole moment
of the . With 107 producedZ particles and with observation of the decay channels
and v
we estimate that
can be determined with an accuracy of about
(1 s.d.). 相似文献
10.
T. F. Hoang 《Zeitschrift fur Physik C Particles and Fields》1994,62(2):343-347
An analysis of secondary hadrons fromZ
0 (91) decays of the LEP experiments indicates that the scaling of
distributions implies the same temperatureT=0.261 GeV for all the secondaries. The multiplicities ofZ
0,K
0, ,..., and computed with their quark contents and the sameT agree with the data. The ratio of
to the phase-space covered by the rapidity distribution, depends only on the energy,
, fore
+
e
– annihilations and
collisions as well. 相似文献
11.
H. Veltman 《Zeitschrift fur Physik C Particles and Fields》1994,62(2):235-251
The level of sensitivity of the processes ZZ, W
+
W
– and
to the Higgs sector of the Standard Model Lagrangian in the energy region between 200 GeV and 1 TeV is examined. The elementary Higgs boson is taken to have a mass less than 1 TeV. Sizeable effects are found in theZZ and
channels if the incoming photons have the same helicity. Also the possibility that the elementary Higgs boson does not exist is examined. Assuming new physics to show up in the TeV energy region the cross sections are evaluated according to the heavy Higgs model. For center of mass energy values close to 1 TeV interesting effects are found in the
channel if the photons have the same helicity. The limit of large Higgs mass is not unique. The parametrization of this arbitrariness may be interpreted as a representation of the new physics. The effects for the processes ZZ and
are investigated. These effects may be correlated to a possible resonance inWW scattering in the TeV region. 相似文献
12.
S. B. Shlosman 《Communications in Mathematical Physics》1989,125(1):81-90
We consider the 2-dimensional Ising model with ferromagnetic nearest neighbour interaction at inverse temperature. LetS
N
=
t
be the total magnetization inside anN×N square box,
per
be the Gibbs state in with periodic b.c., andm() be the spontaneous magnetization. We show the existence of the limit
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