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1.
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
2.
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
3.
4.
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
5.
K. O. Zell H. -G. Friederichs B. Heits D. Hippe H. W. Schuh P. von Brentano C. Protop 《Zeitschrift für Physik A Hadrons and Nuclei》1976,3(3):371-380
77Se has been investigated by the reaction74Ge(,n) at 14 MeV. Gamma singles spectra, gamma angular distributions and gamma-gamma coincidences have been taken. A level scheme has been established, spins and parities have been assigned. States of a rotational band on the 1/2– ground state, a rotational band on the 5/2– 249.7 keV state and an anormal band have been identified.
Nuclear Reaction
74Ge(,n )E
=14 MeV; measuredE
,I
,--Coin.,-ang. distr.77Se deduced levels,J, . Enriched target, Ge (Li). 相似文献
6.
7.
8.
9.
A. Möbius 《Zeitschrift für Physik B Condensed Matter》1990,79(2):265-273
A detailed phenomenological re-analysis of previously published conductivity data, (T, x), is presented. It is based on the investigation of differences, (T, x
1)–(T, x
2). In this way, the cusp-like low-temperature term is amplified against the other temperature dependent contributions. This term can be described by
wherep=0.19±0.03. It is present, if (4.2 K,x) exceeds 260 –1 cm–1, at least up to (4.2 K,x)1350 –1 cm–1 and forT60 K. But it is absent, if (4.2 K,x)180 –1 cm–1. The disappearance of this contribution should be related to the metal-semiconductor transition, taking place atx
c
0.14. On the other hand, the presence of a term proportional toT
1/2, as predicted by Altshuler and Aronov, seems unlikely.It is argued that the term
should be related to the interplay of electron-electron interaction and disorder. The comparison with data from the literature shows that this contribution might also be present in heavily doped crystalline semiconductors. 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.
Consider the Schrödinger equation –u+V(x)u=u on the intervalI, whereV(x)0 forxI and where Dirichlet boundary conditions are imposed at the endpoints ofI. We prove the optimal bound
相似文献
12.
13.
Maria Hoffmann-Ostenhof Thomas Hoffmann-Ostenhof 《Communications in Mathematical Physics》1988,117(1):49-77
Let
R
=
n
B
R, wheren3 andB
R={x
n
:|x|R}. We investigate the asymptotics of real valued solutions L
2(
R
) of the Schrödinger equation (–+V–E)=0, whereE<0>0>V(x)0 for |x|: LetD denote an unbounded nodal domain of (i.e. a component of
R
{x:(x)=0}), and letS(r)={yS
n–1:ryD} withS
n–1 the unit sphere in
n
. Under suitable assumptions onV it is shown that for some >0,
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