Precision measurement of scaled momentum, charge multiplicity, and thrust in νμN and interactions

Abstract

We report the first precision measurements of the scaled momentum, the charge multiplicity, and the thrust of hadronic jets in the Breit frame in Deep Inelastic Scattering ν µ N andν µ N charged current events over the Q 2 range from 1 to 100 GeV 2 . The neutrino data, obtained in the NOMAD experiment at the CERN SPS, extend the Q 2 -evolution of these parameters by two orders of magnitude, and with commensurate precision, when compared to those reported by the ep and e + e − experiments.

Hadron multiplicity in lepton–nucleon interactions

“…2. As it shown in [1] the NOMAD multiplicity values n ch are very close to < n ch > /2 results from e + e − experiment [11] at energy E = √ s and < n ch > from ep andν µ p at E = Q. In Fig.…”

“…Such an analysis has been performed recently in Ref. [1]. It has also been found that a perturbative QCD calculation results in a good description of the charged hadron multiplicity < n ch > measured in e + e − annihilation and ep DIS at initial energies E = √ s = Q > 5 GeV/c [1], whereas a similar calculation of < n ch > in the current region of processes ν(ν) p → µ − (µ + ) h X cannot reproduce the NOMAD data at Q < 5 GeV/c .…”

“…[1]. It has also been found that a perturbative QCD calculation results in a good description of the charged hadron multiplicity < n ch > measured in e + e − annihilation and ep DIS at initial energies E = √ s = Q > 5 GeV/c [1], whereas a similar calculation of < n ch > in the current region of processes ν(ν) p → µ − (µ + ) h X cannot reproduce the NOMAD data at Q < 5 GeV/c . This discrepancy is an important motivation for the present analysis of inelastic neutrino-nucleon interactions within the framework of the quark-gluon string model (QGSM) [2,3], which is essentially equivalent to the dual parton model (DPM) developed in Refs.…”

“…The main difference from the previous study is that we now use the Monte Carlo (MC) generation of hadrons produced from the decay of colorless strings. This pro-cedure allows us to analyze all the observables measured experimentally and make a comparison with recent data [1]. In the QGSM [2,3], hadron production in the reactions ν(ν) p → µ − (µ + ) h X is described in terms of planar and cylindrical graphs, as shown in Fig.…”

Determination ofαsat NLO*+NNLL from a global fit of the low-zparton-tohadron fragmentation functions ine+e−and DIS collisions

“…[40] in the current hemisphere of the Breit (or "brick wall") frame where the incoming quark scatters off the photon and returns along the same axis. In addition, we include also into our global fit the 55 direct measurements of FF moments (mostly multiplicity, peak, and width) from H1 [41] and ZEUS [42] experiments in e ± -p at HERA, and NOMAD (ν-N scattering) [43], covering the range of four-momentum transfers Q ≈ 1-180 GeV. The total final number of FF moments extracted from the DIS jet data is 160 and, thus, the combined global fit of e + e…”