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1.
We use a quite concrete and simple realization of sl
q
(2, ) involving finite difference operators. We interpret them as derivations (in the noncommutative sense) on a suitable graded algebra, which gives rise to the noncommutative scheme 1 II 1* as the counterpart of the standard 1 = Sl(2, )/B. 相似文献
2.
The ring (Frobenius algebra) of local observables for topological -models on 1 with values in the grassmannianG(s, n) is known to be the same as the quotient of the homology ring of the target space by the (inhomogeneous) ideal generated by the so-called quantum correction. While the need for a quantum correction comes from algebraic motivations in field theory, the aim of this paper is to understand its geometric meaning. The simple examples of 1 n models tell us that the quantum correction comes by restriction on the boundary of the moduli spaces which allows to compute intersections on moduli spaces of lower degrees. We will check this point of view for the case of 1 G(s,n) models, yielding a proof of the algebraic result from physics in terms of the geometry of the -model itself.Work partially supported by National Project 40% Probabilistic and geometrical methods in Mathematical Physics and by CNR-Gruppo Nazionale di Fisica Matematica. 相似文献
3.
G. T. Jones R. W. L. Jones B. W. Kennedy D. R. O. Morrison 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 F. W. Bullock S. Burke 《Zeitschrift fur Physik C Particles and Fields》1993,58(3):375-386
Evidence is presented for diffractive production of -mesons and of -systems invp and
chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeVE
v
<60 gev=" the=" cross=" sections=" for=" diffractive=">60> and diffractive production are found to be (0.64±0.14 (stat.)±0.08 (syst.))% and (0.28±0.08 (stat.)±0.04 (syst.))% of the charged-current cross section. The diffractive signal is consistent with being entirely due to diffractivea
1 production. However, the data cannot distinguish between diffractivea
1 and diffractive nonresonant production. The experimental distributions ofW, Q
2,x
Bj
andy
Bj
for diffractive and events are consistent with model predictions. 相似文献
4.
Tomoyuki Takenawa 《Communications in Mathematical Physics》2004,246(1):19-42
A 3 dimensional analogue of Sakais theory concerning the relation between rational surfaces and discrete Painlevé equations is studied. For a family of rational varieties obtained by blow-ups at 8 points in general position in 3, we define its symmetry group using the inner product that is associated with the intersection numbers and show that the group is isomorphic to the Weyl group of type E7(1). By parametrizing the configuration space by means of elliptic curves, the action of the Weyl group and the dynamical system associated with a translation are explicitly described. As a result, it is found that the action of the Weyl group on 3 preserves a one parameter family of quadratic surfaces and that it can therefore be reduced to the action on 1×1. 相似文献
5.
We give a noncommutative version of the complex projective space 2 and show that scalar QFT on this space is free of UV divergencies. The tools necessary to investigate quantum fields on this fuzzy 2 are developed and several possibilities to introduce spinors and Dirac operators are discussed. 相似文献
6.
Every simply connected Lorentz symmetric space of dimensionn3 has a symmetric quotient which can be conformally imbedded in a quadric of the projective space n+1 (R). 相似文献
7.
8.
Nikolai N. Nikolaev Vladimir R. Zoller 《Zeitschrift fur Physik C Particles and Fields》1992,56(4):623-628
One expects a similarity of the energy dependence of the difference
tot(*p)–
tot(*n) for virtual (deep inelastic scatteringQ
2m
2) and real (Q
2=0) photons. Previous analysis of D structure functions with allowence for nuclear shadowing (NS) in the deuteron has led to conclusion that
tot(*p)–
tot(*n)<0>0>x<0.015. the=" early=" evidence=" from=" the=" real=" photoproduction=" data=">0.015.>
tot(p)–
tot(n)<0. we=" critically=" reexamine=" determinations=" of=" the=">0.>
tot(p)–
tot(n), using more accurate calculations of NS correction to
tot(D), and discuss a possibility of
tot(n)
tot(p) at moderately high energies. 相似文献
9.
U. Meyer 《Letters in Mathematical Physics》1995,35(2):91-97
Associated to the standard SU
q
(n) R-matrices, we introduce quantum spheresS
q
2n-1
, projective quantum spaces
q
n-1
, and quantum Grassmann manifoldsG
k(
q
n
). These algebras are shown to be homogeneous spaces of standard quantum groups and are also quantum principle bundles in the sense of T. Brzeziski and S. Majid. 相似文献
10.
J. Brenneisen D. Grathwohl M. Lickert R. Ott H. Röpke J. Schmälzlin P. Siedle B. H. Wildenthal 《Zeitschrift für Physik A Hadrons and Nuclei》1995,352(2):149-159
The systematics of-decay modes and radiative widths of highly excited states in28Si has been extended by taking-ray spectra on 60 resonances of the27Al(p,) reaction in the range 1097 keVE
p
4492 keV (12643 keVE
x
15915 keV) and on the24Mg(,) resonances atE
=3355, 3431, 4003 keV (E
x
=12860, 12925, 13 415 keV). The-decay modes of levels in the sub-resonance region (E
x
=10–12.5 MeV) were studied with both the27
A1(p, ) reaction and the27
A1(d, n) reaction at Ed=4,5,6 MeV. Information on radiative widths of levels was obtained by measuring the resonance strengthsS
=(2I+1)
p
/ for 52 resonances of the27Al(p, ) reaction with an emphasis on prospective T=1 states. 相似文献
11.
12.
Production of strange and charm particles by hadron-proton collisions is analyzed in terms of a fire-ball (FB) model assuming the multiplicity of secondaries of a given massm, to be proportional to the FB mass: n(m)M
*, the FB kinematics being determined by the Feynman-Yang scaling, as in the case of production. It is found that (m)1/m
2 and that, using this property together with the scaling, no-free-parameter fits to currently available data of strange and charm particles frompp and p collisions are satisfactory, as well as for the photoproduction of charm mesonD and charm hyperon
c
. 相似文献
13.
V. G. Knizhnik 《Communications in Mathematical Physics》1987,112(4):567-590
The properties of analytic fields on a Riemann surface represented by a branch covering of 1 are investigated in detail. Branch points are shown to correspond to the vertex operators with simple conformal properties. As applications we compute determinants of
operators forZ
n
-symmetric surfaces and obtain various representations for the two-loop measure in the bosonic string theory together with various identities for theta-functions of hyperelliptic surfaces. We also present an integral representation for the quantum part of the twist field correlation functions, which describe propagation of the string on the orbifold background. We also calculate the quantum part of the structure constants of the twist-field operator algebra, generalizing the results of Dixon, Friedan, Martinec, and Shenker. 相似文献
14.
We discuss the production of soft photons in high energy hadron-hadron collisions. We present a model where quarks and antiquarks in the hadrons emit synchrotron light when being deflected by the chromomagnetic fields of the QCD vacuum, which we assume to have a nonperturbative structure. This gives a source of prompt soft photons with frequencies <~300 mev=" in=" the=" c.m.=" system=" of=" the=" collision=" in=" addition=" to=" hadronic=" bremsstrahlung.=" in=" comparing=" the=" frequency=" spectrum=" and=" rate=" of=">~300>synchrotron photons to experimental results we find some supporting evidence for their existence. We make an exclusive-inclusive connection argument to deduce from the synchrotron effect a behaviour of the neutron electric formfactorG
E
n
(G
2) proportional to (Q
2)1/6 forQ
220 fm–2. We find this to be consistent with available data. In our view, soft photon production in high energy hadron-hadron and lepton-hadron collisions as well as the behaviour of electromagnetic hadron formafactors for lowQ
2 are thus sensitive probles of the nonperturbative structure of the QCD vacuum. 相似文献
15.
T. Ahmed S. Aid V. Andreev B. Andrieu R. -D. Appuhn M. Arpagaus A. Babaev J. Baehr J. Bán P. Baranov et al. 《Zeitschrift fur Physik C Particles and Fields》1995,66(4):529-542
We present an experimental study of theepe+p andepe+X processes using data recorded by the H1 detector in 1993 at the electron-proton collider HERA. These processes are employed to measure the luminosity with an accuracy of 4.5 %. A subsample of theepe+X events in which the hard photon is detected at angles
0.45 mrad with respect to the incident electron direction is used to verify experimentally the size of radiative corrections to theepeX inclusive cross section and to investigate the structure of the proton in theQ
2 domain down to 2 GeV2, lower than previously attained at HERA.Supported by the Bundesministerium für Forschung und Technologie, FRG under contract numbers 6AC17P, 6AC47P, 6DO57I, 6HH17P, 6HH27I, 6HD17I, 6HD27I, 6KI17P, 6MP17I, and 6WT87P 相似文献
16.
M. Ya. Balatz I. M. Belyaev V. A. Dorofeev G. B. Dzubenko I. M. Filimonov S. V. Frolov S. V. Golovkin Yu. L. Grishkin M. V. Gritzuk A. D. Kamenskii G. K. Kliger A. P. Kozevnikov V. Z. Kolganov A. S. Konstantinov Yu. V. Korchagin V. P. Kubarovskii N. Yu. Kulman A. I. Kulyavtsev V. F. Kurshetsov A. E. Kushnirenko V. S. Lakaev L. G. Landsberg G. S. Lomkatzi V. V. Molchanov V. A. Mukhin A. P. Nilov Yu. B. Novoghilov V. A. Prutskoi A. I. Sitnikov V. T. Smolyankin V. I. Solyanik D. V. Vavilov V. A. Victorov V. E. Vishnyakov 《Zeitschrift fur Physik C Particles and Fields》1994,61(3):399-405
In the experiments at the SPHINX facility in the 70 GeV proton beam of the IHEP accelerator the diffractive production reactionsp+N[(1385)0
K
+] +N andp+N[(1385)0
K
+]+N+ (neutral particles) were studied. In the effective mass spectra of the [(1385)0
K
+] system in these processes there were no signals from the anomalously narrow baryon stateN
(1960) which had been observed earlier in the measurement at the BIS-2 setup.SPHINX Collaboration (IHEP-ITEP) 相似文献
17.
T. A. Armstrong R. P. Barnes M. Benayoun W. Beusch I. J. Bloodworth J. N. Carney D. DiBari C. J. Dodenhoff C. Evangelista D. Evans B. Ghidini B. R. French M. Girone A. Jacholkowski J. B. Kinson A. Kirk K. Knudson V. Lenti V. Manzari F. Navach A. Palano E. Quercigh M. Sené R. Sené G. Vassiliadis O. Villalobos Baillie M. F. Votruba 《Zeitschrift fur Physik C Particles and Fields》1992,54(3):371-376
The reactionppp
f
(
+
–
)p
s
, where the
+
–
system is centrally produced, has been studied at 300 GeV/c. The
+
–
mass spectrum shows evidence for a
0
decay mode of the (958) andf
1 (1285). The branching ratio (f
1(1285)
+
+)/(f
1(1285)
0
) is found to be 5.0±0.7. No evidence is found for a
0(770) decay mode of theE/f
1 (1420) for which an upper limit BR (E/f
1(1420)
0
)<0.08 at=" 95%=" cl=" is=">0.08> 相似文献
18.
We calculate exactly the contribution of instanton fields to the partition function of
n–1 models in two dimensions. Forn=2, the pure instanton gas is infrared finite, infinitely dense and generates a mass dynamically. Forn3, the gas corresponds to a system with complicatedn-body interactions, whose properties are yet to be explored. 相似文献
19.
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
20.
New measurements of the reactione
+
e
– confirm previous evidence for the decay1 and provide a strong constraint on the mass of the1. The results from a detailed analysis of these data are compared with those from a corresponding analysis of new data on the reactione
+
e
–. It is shown that
in accord with expectation. This identification of a strong1 decay supports a previous claim that the1 and theC(1480), observed in the channel, cannot be different manifestations of the same particle. 相似文献