Drell-Yan lepton angular distributions in perturbative QCD

Lambertsen, Martin; Vogelsang, Werner

doi:10.1103/physrevd.93.114013

Cited by 44 publications

(52 citation statements)

References 72 publications

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“…Similarly to the SIDIS case, in the kinematic limit q 2 T Q 2 the structure function F 2 U U can be neglected (for measurement and estimates of this structure function see, e.g., ref. [45] and references therein).…”

Section: Drell-yan and Z Productionmentioning

confidence: 99%

Extraction of partonic transverse momentum distributions from semi-inclusive deep-inelastic scattering, Drell-Yan and Z-boson production

Bacchetta

Delcarro

Pisano

et al. 2017

J. High Energ. Phys.

217

239

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We present an extraction of unpolarized partonic transverse momentum distributions (TMDs) from a simultaneous fit of available data measured in semi-inclusive deep-inelastic scattering, Drell-Yan and Z boson production. To connect data at different scales, we use TMD evolution at next-to-leading logarithmic accuracy. The analysis is restricted to the low-transverse-momentum region, with no matching to fixed-order calculations at high transverse momentum. We introduce specific choices to deal with TMD evolution at low scales, of the order of 1 GeV 2 . This could be considered as a first attempt at a global fit of TMDs.

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Section: Drell-yan and Z Productionmentioning

confidence: 99%

Extraction of partonic transverse momentum distributions from semi-inclusive deep-inelastic scattering, Drell-Yan and Z-boson production

Bacchetta

Delcarro

Pisano

et al. 2017

J. High Energ. Phys.

217

239

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“…In the high-q T region, on the other hand, the cancellation takes place between the asymptotic piece and the W term. The situation is more complicated if also the angular dependence of the DY cross section is taken into consideration (see, e.g., [27][28][29][30]). Both regimes, q T Q and q T ∼ Q, as well as their matching, must be under theoretical control in order to have a proper understanding of the physics of the Drell-Yan process.…”

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confidence: 99%

Difficulties in the description of Drell-Yan processes at moderate invariant mass and high transverse momentum

et al. 2019

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We study the Drell-Yan cross section differential with respect to the transverse momentum of the produced lepton pair. We consider data with moderate invariant mass Q of the lepton pair, between 4.5 GeV and 13.5 GeV, and similar (although slightly smaller) values of the transverse momentum qT . We approach the problem by deriving predictions based on standard collinear factorization, which are expected to be valid toward the high-qT end of the spectrum and to which any description of the spectrum at lower qT using transverse-momentum dependent parton distributions ultimately needs to be matched. We find that the collinear framework predicts cross sections that in most cases are significantly below available data at high qT . We discuss additional perturbative and possible non-perturbative effects that increase the predicted cross section, but not by a sufficient amount. PACS numbers: 12.38.Bx, 12.39.St, 13.85.Qk I. INTRODUCTIONThe Drell-Yan (DY) process [1] is one of the main sources of information about the internal structure of the nucleon (for a recent review, see [2]). Factorization theorems were first established for DY [3], and global extractions of parton distribution functions (PDFs) heavily rely on measurements of the DY cross section differential in the rapidity of the produced boson (see, e.g., [4,5] and references therein). DY processes also offer the possibility to access transverse momentum distributions (TMDs) [6][7][8][9][10][11][12][13][14][15], if the cross section is kept differential in the transverse momentum of the produced boson.Considering the invariant mass of the produced boson, Q, its transverse momentum, q T , and a typical QCD scale, Λ QCD , we can distinguish a region of "high transverse momentum" 1 where Λ QCD q T ∼ Q and a region of "low transverse momentum" where q T Q. In the first region, the cross section should be well described by a collinear factorization framework in terms of collinear PDFs convoluted with a partonic hard scattering calculated up to a fixed order in α s . This calculation is nowadays possible even up to order α 3 s (NNLO) [17], but most of the phenomenology is carried out at order α 2 s (NLO) [18][19][20][21][22][23][24][25] or even only order α s (LO). In the low transverse momentum region, the cross section should be described in the framework of TMD factorization, which also incorporates the effects of the resummation of large logarithms in q T /Q. The all-order corrections dominating the cross section in this region are embodied in the so-called "W term" of the Collins-Soper-Sterman formalism [26]. The matching of the collinear formalism at high-q T with the TMD resummation at low-q T is usually performed through the introduction of the so-called "Y term", i.e., the difference of the fixed-order perturbative result and the asymptotic expansion of the resummed result. In the low-q T region, the asymptotic piece and the fixed-order one ideally cancel each other, leaving only the W term. In the high-q T region, on the other hand, the cancellation takes pla...

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“…They were recently measured [45], and it seems that in fact larger corrections are needed. This topic was recently covered in [58] One may wonder, why the property of the matrix element of single gluon emission extends to other cases, when final states feature quark or there are two outgoing partons, gluonic or quarks. In principle, to understand this, one would need to study the properties of all spin amplitudes, e.g.…”

Section: Main Features Of Resultsmentioning

confidence: 99%

Separating electroweak and strong interactions in Drell–Yan processes at LHC: leptons angular distributions and reference frames

Richter-Wąs

Wa̧s

2016

Eur. Phys. J. C

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Among the physics goals of LHC experiments, precision tests of the Standard Model in the Strong and Electroweak sectors play an important role. Because of nature of the proton-proton processes, observables based on the measurement of the direction and energy of leptons provide the most precise signatures. In the present paper, we concentrate on the angular distribution of Drell-Yan process leptons, in the lepton-pair rest-frame. The vector nature of the intermediate state imposes that distributions are to a good precision described by spherical polynomials of at most second order. We show that with the proper choice of the coordinate frames, only one coefficient in this polynomial decomposition remains sizable, even in the presence of one or two high p T jets. The necessary stochastic choice of the frames relies on probabilities independent from any coupling constants. This remains true when one or two partons accompany the lepton pairs. In this way electroweak effects can be better separated from strong interaction ones for the benefit of the interpretation of the measurements. Our study exploits properties of single gluon emission matrix elements which are clearly visible if a conveniently chosen form of their representation is used. We rely also on distributions obtained from matrix element based Monte Carlo generated samples of events with two leptons and up to two additional partons in test samples. Incoming colliding protons' partons are distributed accordingly to PDFs and are strictly collinear to the corresponding beams.

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Drell-Yan lepton angular distributions in perturbative QCD

Cited by 44 publications

References 72 publications

Extraction of partonic transverse momentum distributions from semi-inclusive deep-inelastic scattering, Drell-Yan and Z-boson production

Extraction of partonic transverse momentum distributions from semi-inclusive deep-inelastic scattering, Drell-Yan and Z-boson production

Difficulties in the description of Drell-Yan processes at moderate invariant mass and high transverse momentum

Separating electroweak and strong interactions in Drell–Yan processes at LHC: leptons angular distributions and reference frames

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