We study the correlation between the fermion composite system and quark spins by using the light-cone quark-diquark model. We do the calculations for $u$-quark and $d$-quark in the fermion system by considering the different polarization configrations of both. The contribution from scalar and axial-vector diquarks is taken into account. The overlap represenation of light-front wavefunctions is used for the calculations. The spin-spin correlations for $u$ and $d$ quarks are presented in transverse impact-parameter plane and transverse momentum plane as well.
We consider quark-photon correlations that have been proposed as a source for single-spin asymmetries in inclusive deep-inelastic scattering. A new sum rule for these correlators is derived and its phenomenological consequences are discussed. The results are interpreted within the context of an intuitive 'electrodynamic lensing' picture.
We have scrutinized the transverse momentum dependent quark-gluon-quark correlation function. We have utilized the light-front quark-diquark model to study the time-reversal-odd interaction-dependent twist-3 gluon distributions which we have obtained from the disintegration of the transverse momentum dependent quark-gluon-quark correlator. Specifically, we have studied the behavior of $\tilde{e}_{L}$ and $\tilde{e}_{T}$ while considering our diquark to be an axial-vector.
We study the transverse momentum dependent quark-gluon-quark correlation function. Using a spectator diquark model, we calculate the eight time-reversal-odd interaction-dependent twist-3 quark distributions appearing in the decomposition of the transverse momentum dependent quark-gluon-quark correlator. In order to obtain finite results, we assume a dipole form factor for the nucleon-quark-diquark coupling, instead of a point-like coupling. The results are compared with the time-reversal-odd interaction-independent twist-3 TMDs calculated in the same model.
We calculate the q q correlation function associated to transverse target lepton-nucleon inclusive deep-inelastic scattering by direct evaluation of the corresponding matrix element. We use the electromagnetic impact parameter potential for a transversely polarized nucleon to define the q q correlation function for each avor in terms of the field components of that avor. The results are compared with the two existing models for the q q correlator. Using the calculated q q correlation function, we estimated the transverse target SSA in IDIS process.
Recently, three new states of $Ξ_c^0$ were observed in the invariant mass spectrum of $Λ^+_cK^-$ by LHCb collaboration. In this work, we use a chiral quark model to investigate these three exited states with the help of Gaussian expansion method both in three-quark structure and in five-quark structure with all possible quantum numbers $IJ^P=\frac{1}{2}(\frac{1}{2})^-$, $\frac{1}{2}(\frac{3}{2})^-$, $\frac{1}{2}(\frac{5}{2})^-$, $\frac{3}{2}(\frac{1}{2})^-$, $\frac{3}{2}(\frac{3}{2})^-$ and $\frac{3}{2}(\frac{5}{2})^-$ . The calculations shows that the 2$S$ states of $Ξ_c'(2579)^0$ and $Ξ_c(26…
Jet handedness as a measure of quark and/or gluon polarizations has been proposed for nearly 30 years. It was demonstrated by measuring the correlation of jet handedness in the electron positron annihilation process. Once parameters are determined, the method could be used to measure quark and/or gluon polarizations in other experiments. The reported data provided evidence for the jet handedness and handedness correlation. However, the jet handedness correlation measured in the electron positron annihilation process from the opposite jets contradicts theoretical prediction by a sign. In order …
We study the correlation between the quark spin and orbital angular momentum inside the pion meson. Similar to the case inside the nucleon, the longitudinal spin-orbit correlation $C_z^{q/π}$ in pion meson can be expressed in terms of the corresponding generalized parton distributions (GPDs) and generalized transverse momentum distributions (GTMDs). This provides new information about the spin structure of the pion. Using the wavefunctions of the pion in the light-cone quark model and the overlap representation for GPDs and GTMDs, we present the analytical results for the quark longitudinal sp…
INFN-Sezione di Catania（意大利国家核物理研究所卡塔尼亚分部）；University of Catania（卡塔尼亚大学）；University of Science and Technology of China（中国科学技术大学）；Anhui University of Science and Technology（安徽理工大学）；Central China Normal University（华中师范大学）；Johann Wolfgang Goethe Universitaet（约翰·沃尔夫冈·歌德法兰克福大学）
In the symmetric string fragmentation recipe adopted by PYTHIA for jet simulations, the transverse momenta of successive quarks are uncorrelated. This is a simplification but has no theoretical reason. Transverse momentum correlations are naturally expected, for instance, in a covariant multiperipheral model of quark hadronization. We propose a simple recipe of string fragmentation which lead to such correlations. The definition of the jet axis and its relation with the primordial transverse momentum of the quark is also discussed.
We analyze, within several parameter scenarios of type-II two-Higgs doublet extensions of the standard model, the impact of heavy neutral Higgs-boson resonances on top-quark pair production and their subsequent decay to dileptonic final states at the LHC (13 TeV). In particular, we investigate the effects of heavy Higgs bosons on top-spin observables, that is, the longitudinal top-quark polarization and top-quark spin correlations. We take into account NLO QCD as well as weak interaction corrections and show that top-spin observables, if evaluated in judiciously chosen top-quark pair invariant…
We consider, for the first time, correlations between produced quarks in p-A collisions in the framework of the Color Glass Condensate. We find a quark-quark ridge that shows a dip at $Δη\sim 2$ relative to the gluon-gluon ridge. The origin of this dip is the short range (in rapidity) Pauli blocking experienced by quarks in the wave function of the incoming projectile. We observe that these correlations, present in the initial state, survive the scattering process. We suggest that this effect may be observable in open charm-open charm correlations at the Large Hadron Collider.
The magnetic moments of $J^P=\frac{3}{2}^+$ decuplet baryons have been calculated in the chiral constituent quark model ($χ$CQM) with explicit results for the contribution coming from the valence quark polarizations, sea quark polarizations, and their orbital angular momentum. Since the $J^P=\frac{3}{2}^+$ decuplet baryons have short lifetimes, the experimental information about them is limited. The $χ$CQM has important implications for chiral symmetry breaking as well as SU(3) symmetry breaking since it works in the region between the QCD confinement scale and the chiral symmetry breaking sca…
The production of heavy flavor quark pairs, including top-anti-top, at the LHC proceeds primarily through gluon fusion. The correlation between the gluon spins affects various spin correlations between the produced quark and anti-quark. Both single spin asymmetries and double correlations of the quark pair spins will be manifest in the subsequent hadronization and decay distributions. For top pairs this is most pronounced. Dilepton, single lepton, and purely hadronic top pair decay channels allow for the extraction of gluon spin information as well as providing a window into possible interacti…
We investigate the relative size of various twist-3 quark-gluon correlation functions relevant to single transverse spin asymmetries (SSAs) in a quark-diquark model of the nucleon. We calculate the quark-gluon correlation function $T_{q,F}(x, x)$ that is responsible for the gluonic pole contribution to the SSAs, as well as $T_{q,F}(0, x)$ and $T_{Δ{q}, F}(0, x)$ responsible for the fermionic pole contributions. We find in both cases of a scalar diquark and an axial-vector diquark that at the first nontrivial order only the $\tq(x, x)$ is finite while all other quark-gluon correlation functions…
The specific effects of the reflective scattering (antishadowing) related to the spin correlations in the top quark production at the LHC are considered. Account for those effects is important in the searches for the signatures of the extra dimensiones. It is shown that significant spin correlations could arise at the LHC energies due to reflective scattering and those can affect the signals of the extra dimensions.
We revisit the effect of CP violating anomalous top-quark couplings in $t\bar{t}$ production and decay. We consider $t\bar{t}$ production through gluon fusion (and light $q{\bar q}$ annihilation) followed by top-quark decay into $bW$ or $b\ellν$. We find explicit analytic expressions for all the triple products generated by the anomalous couplings that fully incorporate all spin correlations. Our results serve as a starting point for numerical simulations for the LHC.
The radiative baryonic decay $\mathcal{B}^{*}\left(\frac{3}{2}\right)\to\mathcal{B}\left(\frac{1}{2}\right)+γ$ is a magnetic dipole $(M1)$ transition. It requires the transition magnetic moment $μ_{\mathcal{B}\left(3/2\right)\to\mathcal{B}\left(1/2\right)}$. The transition magnetic moments for the helicities $1/2$ and $3/2$ are evaluated in the frame work of constituent quark model in which the intrinsic spin and the magnetic moments of quarks $u,d$ and $s$ play a key role. Within this framework, the radiative decays $Δ^{+}\to p +γ$, $Σ^{*0}\to Λ+γ$, $Σ^{*+}\to Σ^{+}+γ$ and $Ξ^{*0}\to Ξ^{0}+γ$…
Correlations between the strange quark mass, strange quark condensate $\langle \bar s s\rangle$, and the kaon partially conserved axial current (PCAC) relation are developed. The key dimensionless and renormalization-group invariant quantities in these correlations are the ratio of the strange to non-strange quark mass $r_m=m_s/m_q$, the condensate ratio $r_c=\langle \bar s s\rangle/\langle \bar q q\rangle$, and the kaon PCAC deviation parameter $r_p=-m_s\langle \bar s s+\bar q q\rangle/2f_K^2m_K^2$. The correlations define a self-consistent trajectory in the $\{r_m,r_c,r_p\}$ parameter space …
Spin correlations of top quarks produced in hadron collisions have not been observed experimentally with large significance. In this Letter, we propose a new variable that may enable demonstration of the existence of spin correlations with 3-4 sigma significance using just a few hundred dilepton events both at the Tevatron and the LHC. Such number of dilepton events has been observed at the Tevatron. At the LHC, it will become available once integrated luminosity of a few hundred inverse picobarns is collected.
