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1.
Within the framework of perturbative quantum chromodynamics we derive the evolution equations for transverse momentum dependent distributions and apply them to the case of semi-inclusive deep inelastic scattering. The evolution equations encode the perturbative component of transverse momentum generated by collinear parton branchings. The current fragmentation is described via transverse momentum dependent parton densities and fragmentation functions. Target fragmentation instead is described via fracture functions. We present, to leading logarithmic accuracy, the corresponding semi-inclusive deep inelastic scattering cross-section, which applies to the entire phase space of the detected hadron. Some phenomenological implications and further developments are briefly outlined. 相似文献
2.
The next-to-leading logarithmic corrections to cross-sections for semi-inclusive deep inelastic scattering from a polarized target are worked out. Predictions for pion asymmetries and pion charge ratios are given. 相似文献
3.
Hadron production in lepton-nucleus deep inelastic scattering is studied in a model including quark energy loss and nuclear absorption. The leading-order computations for hadron multiplicity ratios are presented and compared with the selected HERMES experimental data with the quark hadronization occurring inside the nucleus by means of the hadron formation time. It is shown that with increase of the energy fraction carried by the hadron, the nuclear suppression on hadron multiplicity ratio from nuclear absorption gets bigger. It is found that when hadronization occurs inside the nucleus, the nuclear absorption is the dominant mechanism causing a reduction of the hadron yield. The atomic mass dependence of hadron attenuation for quark hadronization starting inside the nucleus is confirmed theoretically and experimentally to be proportional to A1/3. 相似文献
4.
M. Anselmino M. Boglione U. D’Alesio A. Kotzinian S. Melis F. Murgia A. Prokudin C. Türk 《The European Physical Journal A - Hadrons and Nuclei》2009,39(1):89-100
We study the Sivers effect in the transverse single spin asymmetries (SSA) for pion and kaon production in semi-inclusive
deep inelastic scattering (SIDIS) processes. We perform a fit of which, by including recent high-statistics experimental data for pion and kaon production from HERMES and COMPASS Collaborations,
allows a new determination of the Sivers distribution functions for quarks and antiquarks with u , d and s flavours. Estimates for forthcoming SIDIS experiments at COMPASS and JLab are given. 相似文献
5.
Atomic mass dependence of hadron production in semi-inclusive deep inelastic lepton-nucleus scattering
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Hadron production in lepton-nucleus deep inelastic scattering is studied in a quark energy loss model. The leading-order computations for hadron multiplicity ratios are presented and compared with the selected HERMES pions production data with the quark hadronization occurring outside the nucleus by means of the hadron formation time. It is found that the obtained energy loss per unit length is 0.440 ± 0.013 GeV/fm for an outgoing quark by the global fit. It is confirmed that the atomic mass number dependence of hadron attenuation is theoretically and experimentally in good agreement with the A2/3 power law for quark hadronization occurring outside the nucleus. 相似文献
6.
Y.Miyachi 《中国物理C(英文版)》2010,34(9)
The HERMES measured azimuthal amplitudes of cross sections and their transverse target single spin asymmetries for hadron productions in semi-inclusive deep inelastic scattering.From the extracted amplitudes,novel patton distribution functions can be studied.The recent results related to Sivers and Boer-Mulders distribution functions are discussed. 相似文献
7.
Y. Miyachi 《中国物理 C》2010,34(9):1494-1497
The HERMES measured azimuthal amplitudes of cross sections and their transverse target single spin asymmetries for hadron productions in semi-inclusive deep inelastic scattering.From the extracted amplitudes,novel parton distribution functions can be studied.The recent results related to Sivers and Boer-Mulders distribution functions are discussed. 相似文献
8.
Alexakhin VY Alexandrov Y Alexeev GD Amoroso A Badełek B Balestra F Ball J Baum G Bedfer Y Berglund P Bernet C Bertini R Birsa R Bisplinghoff J Bradamante F Bravar A Bressan A Burtin E Bussa MP Cerini L Chapiro A Cicuttin A Colantoni M Colavita AA Costa S Crespo ML d'Hose N Dalla Torre S Dasgupta SS De Masi R Dedek N Denisov OY Dhara L Diaz Kavka V Dolgopolov AV Donskov SV Dorofeev VA Doshita N Duic V Dünnweber W Efremov A Ehlers J Eversheim PD Eyrich W Fabro M Faessler M Fauland P Ferrero A 《Physical review letters》2005,94(20):202002
First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors. 相似文献
9.
Recent measurements from the HERMES and SMC Collaborations show a remarkably large azimuthal single-spin asymmetries AUL and AUT of the proton in semi-inclusive pion leptoproduction γ*(q)p→πX. We show that final-state interactions from gluon exchange between the outgoing quark and the target spectator system lead to single-spin asymmetries in deep inelastic lepton–proton scattering at leading twist in perturbative QCD; i.e., the rescattering corrections are not power-law suppressed at large photon virtuality Q2 at fixed xbj. The existence of such single-spin asymmetries requires a phase difference between two amplitudes coupling the proton target with Jzp=±1/2 to the same final-state, the same amplitudes which are necessary to produce a nonzero proton anomalous magnetic moment. We show that the exchange of gauge particles between the outgoing quark and the proton spectators produces a Coulomb-like complex phase which depends on the angular momentum Lz of the proton's constituents and is thus distinct for different proton spin amplitudes. The single-spin asymmetry which arises from such final-state interactions does not factorize into a product of distribution function and fragmentation function, and it is not related to the transversity distribution δq(x,Q) which correlates transversely polarized quarks with the spin of the transversely polarized target nucleon. 相似文献
10.
The azimuthal asymmetry in deep inelastic scattering is calculated in first order QCD for nonvanishing intrinsic transverse momentum; the hadronization is simulated with a Monte-Carlo program. It turns out that, within our scheme, the asymmetry data are mainly sensitive to the intrinsic transverse momentum. The QCD contribution to the asymmetry is small. 相似文献
11.
The longitudinal and transverse properties of the QCD contribution to semi-inclusive deep inelastic scattering is worked out within the soft gluon resummation procedure. The Λ parameter needed to reproduce the data is in agreement with the value extracted from scaling violations. The intrinsic transverse momentum squared of a quark inside a proton is around 0.45 GeV2. Predictions for the transverse correlations of two outgoing pions are guven. 相似文献
12.
B. Andersson G. Gustafson L. Lönnblad U. Pettersson 《Zeitschrift fur Physik C Particles and Fields》1989,44(4):625-632
A superfield action for the relativistic massless superparticle as a spinning particle is presented in the new gauge. The symmetries in the relativistic superparticle theory, that is to say, the invariances under, the reparametrization and the local supersymmetry-transformation in the parameter space, are manifest in this formalism. It is clear how these two kinds of transformations descend from a unified origin to be called “super-reparametrization”, which is a restricted form of the general coordinate transformation in the superspace. The action is manifestly invariant under these transformation by its constructions The minimal coupling with electromagnetic field is also constructed in the superfield formalism, and a manifestly invariant superfield action for the interacting superparticle is presented in our gauge. The formalism is extended to the construction of an action for theN=2 superparticle. 相似文献
13.
Azimuthal and single spin asymmetries play a crucial role in the study of the spin structure of hadrons in terms of their elementary constituents. Exploiting them to uncover information over subtle distribution and fragmentation functions, which cannot easily by accessed in other ways, is what this talk is about. 相似文献
14.
Qian X Allada K Dutta C Huang J Katich J Wang Y Zhang Y Aniol K Annand JR Averett T Benmokhtar F Bertozzi W Bradshaw PC Bosted P Camsonne A Canan M Cates GD Chen C Chen JP Chen W Chirapatpimol K Chudakov E Cisbani E Cornejo JC Cusanno F Dalton MM Deconinck W de Jager CW De Leo R Deng X Deur A Ding H Dolph PA Dutta D El Fassi L Frullani S Gao H Garibaldi F Gaskell D Gilad S Gilman R Glamazdin O Golge S Guo L Hamilton D Hansen O Higinbotham DW Holmstrom T Huang M Ibrahim HF Iodice M Jiang X Jin G 《Physical review letters》2011,107(7):072003
We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations. 相似文献
15.
It is shown that the recent Fermilab μp data are compatible with field theoretic expectations, based on a conventional small uncharmed SU(3) symmetric sea and a charmed sea component consistent with low- and high-energy neutrino data. 相似文献
16.
17.
C. Adloff et al. 《The European Physical Journal C - Particles and Fields》1999,10(3):373-393
The electroproduction of and mesons is studied in elastic, quasi-elastic and inclusive reactions for four momentum transfers and photon-proton centre of mass energies GeV. The data were taken with the H1 detector at the electron proton collider HERA in the years 1995 to 1997. The total virtual
photon-proton cross section for elastic production is measured as a function of and W. The dependence of the production rates on the square of the momentum transfer from the proton (t) is extracted. Decay angular distributions are analysed and the ratio of the longitudinal and transverse cross sections is
derived. The ratio of the cross sections for quasi-elastic and meson production is measured as a function of . The results are discussed in terms of theoretical models based upon perturbative QCD. Differential cross sections for inclusive
and inelastic production of mesons are determined and predictions within two theoretical frameworks are compared with the data, the non-relativistic
QCD factorization approach including colour octet and colour singlet contributions, and the model of Soft Colour Interactions.
Received: 10 March 1999 / Published online: 8 September 1999 相似文献
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19.
J.J. Aubert G. Bassompierre K.H. Becks C. Best E. Böhm X. de Bouard F.W. Brasse C. Broll S. Brown J. Carr R.W. Clifft J.H. Cobb G. Coignet F. Combley G.R. Court J.M. Crespo P.F. Dalpiaz S.J. Wimpenny 《Physics letters. [Part B]》1980,95(2):306-310
The transverse momenta of charged hadrons produced in high energy muon-proton scattering have been studied. The average squared transverse momentum 〈p2⊥〉 shows a strong dependence on z = Eh/v characteristic of intrinsic momentum effects and a significant rise as a function of s = W2. The W2, q2, x and z dependences of the data are compared with the predictions of a perturbative QCD model. 相似文献
20.
Richard Moore 《Nuclear Physics B》1981,191(1):113-124
QCD predictions on the transverse momentum of charmed quarks produced in neutrino production are presented and contrasted to similar predictions of the transverse momentum of jets in electroproduction. The effects of including charmed quark mass are also considered and turn out to be significant. 相似文献