NLO QCD method of the polarized semiinclusive DIS data analysis

Sissakian, A.; Shevchenko, O.Yu.; Ivanov, О. N.

doi:10.1103/physrevd.73.094026

Cited by 16 publications

(24 citation statements)

References 24 publications

(43 reference statements)

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“…An alternative way to measure transversity from the Collins asymmetries alone is via the so-called "difference asymmetries," which allow extracting combinations of the u and d quark transversity without knowing the Collins FF. This method was proposed a long time ago [22][23][24] to access the helicity PDFs and has been used by the SMC Collaboration [25]. It was also included in the COMPASS proposal [26] to measure both longitudinal and transverse spin asymmetries.…”

Section: Introductionmentioning

confidence: 99%

Transversity distributions from difference asymmetries in semi-inclusive DIS

et al. 2019

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In recent years information on the transversity distribution h 1 has been obtained by combining the Collins asymmetry results from semi-inclusive deep inelastic scattering (SIDIS) data on transversely polarized nucleon targets with the information on the fragmentation function of a transversely polarized quark from the asymmetries measured in e þ e − annihilation into hadrons. An alternative method was proposed a long time ago, which does not require the e þ e − data but allows one to get ratios of the u and d quark transversity distributions from the SIDIS data alone. The method utilizes the ratio of the difference of the Collins asymmetries of positively and negatively charged hadrons produced on transversely polarized proton and deuteron targets. We have applied this method to the COMPASS proton and deuteron data and extracted the ratio h d v 1 =h u v 1 . The results are compared to those obtained in a previous point-by-point extraction based both on SIDIS and e þ e − data.

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Section: Introductionmentioning

confidence: 99%

Transversity distributions from difference asymmetries in semi-inclusive DIS

et al. 2019

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“…In this situation of especial importance becomes the direct ∆q extraction in NLO QCD, where (just as in LO QCD) the central values of asymmetries and their uncertainties directly propagate to the extracted ∆q values and their errors. The such NLO QCD method, free of any fitting procedure with a lot of parameters, was elaborated in the sequel of papers [35] (see review [36] for details). At present the respective analysis of the whole existing polarized DIS and SIDIS data is in preparation.…”

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confidence: 99%

Polarized parton distributions from NLO QCD analysis of world DIS and SIDIS data

2009

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The combined analysis of polarized DIS and SIDIS data is performed in NLO QCD. The new parametrization on polarized PDFs is constructed. The uncertainties on PDFs and their first moments are estimated applying the modified Hessian method. The especial attention is paid to the impact of novel SIDIS data on the polarized distributions of light sea and strange quarks. In particular, the important question of polarized sea symmetry is studied in comparison with the latest results on this subject. : 13.65.Ni, 13.60.Hb, 13.88.+e Since the observation of the famous spin crisis in 1987 [1] one of the most intriguing and still unsolved problems of the modern high energy physics is the nucleon spin puzzle. The key component of this problem, which attracted the great both theoretical and experimental efforts during many years is the finding of the polarized parton distributions functions (PDFs) in nucleon. PACSThe analysis of data on inclusive polarized DIS enables us to extract such important quantities as the singlet ∆Σ(x, Q 2 ) and nonsinglet ∆q 3 (x, Q 2 ), ∆q 8 (x, Q 2 ) combinations of the polarized PDFs, and, thereby, the sums of valence and sea PDFs ∆q + ∆q ≡ ∆q V + 2∆q. Besides, dealing with DIS data, the gluon helicity distribution ∆G(x, Q 2 ) is determined due to the evolution in singlet sector and weak dependence on ∆G of the polarized structure function g 1 in NLO QCD. However, even for singlet combinations ∆u + ∆ū, ∆d + ∆d, ∆s + ∆s, considered as well-determined within DIS, we still meet the problem: there are only two equations corresponding to inclusive asymmetries A 1 measured on proton and deuteron targets from which we should determine three unknown combinations ∆q 3 (x), ∆q 8 (x) and ∆Σ(x) (or, alternatively, ∆u + ∆ū, ∆d + ∆d, ∆s + ∆s). So, it is unavoidable to involve some additional assumptions performing the fitting procedure for the purely inclusive DIS data. Moreover, DIS data can not help us to solve the important problem of valence and sea PDFs separation.The basic 4 process which enables us to solve these problems is the process of semiinclusive DIS (SIDIS). However, until recently the quality of the polarized SIDIS data was rather poor, so that its inclusion in the analysis did not helped us [2] to solve the main task of SIDIS measurements: to extract the polarized sea and valence PDFs of all active flavors. Only in 2004 the first polarized SIDIS data with the identification of produced 1 email: sisakian@jinr.ru 2 email: shev@mail.cern.ch 3 email: ivon@jinr.ru 4 As long as no neutrino factory is built and no hyperdense polarized target is created, we cannot study the DIS processes with the neutrino beam, which would enable us to find the polarized valence and sea quark distributions separately.

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“…Then, the idea of TM was successfully applied in the leading ln 2 x approximation, where we found diagonal solutions [5]. Also Sissakian, Shevchenko and Ivanov used the TM technique in their NLO analyses of SIDIS data, incorporating polynomial expansion [6,7]. Several years ago, we derived the DGLAP-type diagonal (no mixing between moments of different orders) and exact evolution equation for the TM in a case of a single truncation [8].…”

Section: Introductionmentioning

confidence: 99%

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Kotlorz¹,

Kotlorz²

2011

Acta Phys. Pol. B

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We review our previous studies of truncated Mellin moments of parton distributions. We show in detail the derivation of the evolution equation for double truncated moments. The obtained splitting function has the same rescaled form as in a case of the single truncated moments. We apply the truncated moments formalism to QCD analyses of the spin structure functions of the nucleon, g 1 and g 2 . We generalize the Wandzura-Wilczek relation in terms of the truncated moments and find new sum rules. We derive the DGLAP-like evolution equation for the twist-2 part of g 2 and solve it numerically. We find also useful relations between the truncated and untruncated moments.

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NLO QCD method of the polarized semiinclusive DIS data analysis

Cited by 16 publications

References 24 publications

Transversity distributions from difference asymmetries in semi-inclusive DIS

Transversity distributions from difference asymmetries in semi-inclusive DIS

Polarized parton distributions from NLO QCD analysis of world DIS and SIDIS data

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