We assess the impact of two-particle--two-hole excitations on the semi-inclusive electron scattering process (e,e'p) using a fully relativistic nuclear model calculation that precisely incorporates antisymmetrization. The calculation encompasses all contributions involving the exchange of a single pion and the excitation of a Delta resonance. Our results are compared with (e,e'p) data on carbon at kinematics where two-nucleon emission dominates. This work represents an essential step towards the microscopic computation of the two-particle--two-hole contribution to semi-inclusive neutrino reactions, crucial in the analysis of neutrino oscillation experiments.
We estimate the heavy quark effective theory parameter λ_1 from inclusive semileptonic B-meson decay spectrum. By using recent CLEO double lepton tagging data of B -> X e nu, which shows the lepton momentum as low as 0.6 GeV, we extracted λ_1 \sim -0.58 GeV^2. We also derived \barΛ\sim 0.46 GeV and |V_{cb}| = 0.041 \pm 0.002.
The dispersive approach to QCD and its applications to inclusive tau lepton hadronic decay and hadronic vacuum polarization function are briefly discussed.
The inclusive tau lepton hadronic decay is studied within Dispersive approach to QCD. The significance of effects due to hadronization is convincingly demonstrated. The approach on hand proves to be capable of describing experimental data on tau lepton hadronic decay in vector and axial-vector channels. The vicinity of values of QCD scale parameter obtained in both channels bears witness to the self-consistency of developed approach.
We study the single-transverse spin asymmetry for open charm production in the semi-inclusive lepton-hadron deep inelastic scattering. We calculate the asymmetry in terms of the QCD collinear factorization approach for $D$ mesons at high enough $P_{h\perp}$, and find that the asymmetry is proportional to the twist-three tri-gluon correlation function in the proton. With a simple model for the tri-gluon correlation function, we estimate the asymmetry for both COMPASS and eRHIC kinematics, and discuss the possibilities of extracting the tri-gluon correlation function in these experiments.
We have applied the Meson Cloud Model to calculate inclusive momentum spectra of pions and kaons produced in high energy proton-proton and proton-nucleus collisions. For the first time these data are used to constrain the cloud cut-off parameters. We show that it is possible to obtain a reasonable description of data, especially the large $x_F$ ($x_F \geq 0.2$) part of the spectrum and at the same time describe (partially) the E866 data on $\bar d - \bar u$ and $\bar d / \bar u$. We also discuss the relative strength of the $πN$ and $πΔ$ vertices. We find out that the corresponding cut-off par…
Single inclusive hadron and jet production in lepton-hadron scattering
Theory Center, Jefferson Lab（理论中心，杰斐逊实验室）；Department of Physics, William & Mary（威廉与玛丽学院物理系）；Department of Physics, Graduate School of Science, Tohoku University（东北大学理学研究科物理学专攻）；Faculty of Science and Technology, Seikei University（圣成大学理工学部）
Inclusive heavy meson photoproduction in $pPb$ and $PbPb$ collisions
Federal University of Pelotas（佩洛塔斯联邦大学）；The Henryk Niewodniczański Institute of Nuclear Physics Polish Academy of Sciences (PAN)（波兰科学院亨利克·涅沃德尼茨基核物理研究所）
It is shown that in semi-inclusive deep inelastic scattering (DIS) of electrons off a complex nucleus A, the detection, in coincidence with the scattered electron, of a nucleus (A-1) in the ground state, as well as of a nucleon and a nucleus (A-2), also in the ground state, may provide unique information on several long standing problems, such as : i) the nature and the relevance of the final state interaction in DIS; ii) validity of the spectator mechanism in DIS; iii) the medium induced modifications of the nucleon structure function; iv) the origin of the EMC effect.
The hadronic properties of the $ρ$ meson produced in the inclusive photonuclear reaction have been investigated. The elementary reaction occurring in the nucleus is assumed as $γN \to ρ^0 N$. The $ρ$ meson, while propagating through the nucleus, interacts with the nuclear particles, and therefore, the properties of the $ρ$ meson can be modified because of this interaction. Being a short-lived particle, the $ρ$ meson decays to various elementary particles, such as, $e^+e^-$, $π^+π^-$, .... etc. The $e^+e^-$ invariant mass, i.e., the $ρ$ meson mass, distribution spectra have been calculated to e…
The scattering of electrons on carbon, calcium, and argon targets are analyzed using an approach that incorporates the contributions to the electromagnetic response functions from the quasielastic (QE), inelastic processes, and two-particle and two-hole meson exchange current ($2p-2h$ MEC). This approach describes well the whole energy spectrum of data at very different kinematics. It is shown that the accuracy of the $(e,e')$ cross section calculations in the region between the QE and delta-resonance peaks, where the $2p-2h$ MEC contribution reaches its maximum value, depends on the momentum …
Color transparency is studied for the $K^+$ meson produced due to large four-momentum transfer in the $(e,e^\prime)$ reaction on nuclei. The variation of the $K^+$ meson color transparency ($K^+$CT) with the photon virtuality, and kaon momentum is investigated. The calculated results for $K^+$CT are compared with the data reported from Jefferson Laboratory.
We review our recent results on exclusive production of $μ^+ μ^-$, heavy quark-antiquark, and meson-antimeson pairs in ultraperipheral, ultrarelativistic heavy ion collisions.
It is shown that, if inclusive lepton scattering off nuclei at high momentum transfer is analyzed in terms of proper scaling variables, useful information on Nucleon-Nucleon short range correlations in nuclei can be obtained. The traditional approach to Y-scaling is critically analyzed and a novel approach to Y-scaling, which incorporates the effects from two- and three-nucleon correlations in nuclei, is illustrated.
The $ω$ and $ϕ$ mesons dominantly decay outside the nucleus because the decay-lengths of them are much larger than the dimension of the nucleus. Therefore, the medium modification of the above mesons is studied through their absorption in the nucleus. CLAS collaboration at Jefferson Laboratory (Jlab) has investigated the absorption of the $ω$ and $ϕ$ mesons by measuring the nuclear transparency ratios for them in the $γA \to ω(ϕ) X \to e^+e^-X$ reaction. The nuclear transparency ratios for both $ω$ and $ϕ$ mesons in the above reactions have been calculated, and those are compared with the expe…
We discuss multi-hadron production in both inelastic neutrino-nucleon interactions in the current fragmentation region and neutrino-nucleus collisions in the target fragmentation region. Our analysis, carried out within the framework of the quark-gluon string model, is mainly focused on the difference between these two processes. We show that the $Q^2$ dependence of hadron multiplicity in the current and target fragmentation regions is indeed completely different. The study of inelastic $ν-A$ scattering in the target fragmentation region also provides new information on nuclear structure at sm…
A relativistic non-local model for the inclusive photoproduction of $η$ mesons from complex nuclei is introduced. The model is based on the dominance of the S$_{11}$(1535) resonance. We compare the results of our calculations with the available data on inclusive cross sections for the nuclei C, Al and Cu. Assuming the resonance propagates freely in the nuclear medium, we find that the calculated angular distribution and energy dependence of the cross sections reproduce the data in a reasonable fashion. The present non-local model allows the inclusion of density dependent mass and width in the …
Charged current inclusive neutrino-nucleus cross sections are evaluated using the superscaling model for quasielastic scattering and its extension to the pion production region. The contribution of two-particle-two-hole vector meson-exchange current excitations is also considered within a fully relativistic model tested against electron scattering data. The results are compared with the inclusive neutrino-nucleus data from the T2K and SciBooNE experiments. For experiments where $\langle E_ν\rangle \sim 0.8$ GeV, the three mechanisms considered in this work provide good agreement with the data.…
