Search arXivSearch

arXiv · 2312.01231

Proposal to PAC 51: Color Transparency in Maximal Rescattering Kinematics

Abstract

With the current highest beam energy at Jefferson Lab and traditional methods, we have exhausted our sensitivity for observing the onset of proton color transparency in a nucleus in A(e,e'p) parallel scattering kinematics for up to $Q^{2}$ = 14 GeV$^{2}$ . One of the disadvantages in A(e,e'p) experiments is that even if a point-like color singlet is produced at such $Q^{2}$, its expansion is unconstrained over the full radius of the nuclei, with the potential to significantly reduce the size of the color transparency effect. Therefore, in order to be sensitive to the effects of color transparency, we enhance the sensitivity of the measurement to the production of a point-like color neutral object prior to the onset of wave-function expansion. In this experiment, we propose a color transparency measurement in maximal rescattering ("dirty") kinematics in deuterium where final-state interactions (FSIs) are known to be huge effects, thereby enhancing our sensitivity to a reduction in FSIs indicative of color transparency. The kinematics in exclusive processes in deuterium can be precisely chosen such that the inter-nucleon distances of the struck and spectator nucleon lead to well-controlled FSIs.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Shujie Li, Carlos Yero, Jennifer Rittenhouse West, Holly Szumila-Vance, Douglas W. Higinbotham. 2023-12-05. Proposal to PAC 51: Color Transparency in Maximal Rescattering Kinematics. https://arxiv.org/abs/2312.01231

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Centrality dependence of charged-particle pseudorapidity density at midrapidity in Pb-Pb collisions at $\mathbf{\sqrt{\textit{s}_{\rm NN}} = 5.36}$ TeV

The ALICE Collaboration reports its first LHC Run 3 measurements of charged-particle pseudorapidity density at midrapidity in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV. Particle multiplicity in high-energy collisions characterises the system geometry, constrains particle-production mechanisms, and is used to estimate initial energy density. Multiplicity also acts as a reference for subsequent measurements as a function of centrality. In this letter, for the first time, charged particles are reconstructed using the upgraded ALICE Inner Tracking System and Time Projection Chamber, while the collision centrality is determined by measuring charged-particle multiplicities with the Fast Interaction Trigger system. Pseudorapidity density, ${\rm d}N_{\rm ch}/{\rm d}η$, is presented, averaged over events, for various centrality classes. Results are shown as a function of pseudorapidity and the average number of participating nucleons ($\langle N_{\mathrm{part}}\rangle$) in the collision. The average charged-particle pseudorapidity density ($\langle {\rm d}N_{\rm ch}/{\rm d}η\rangle$) at midrapidity ($|η|<0.5$) is 2010 $\pm$ 53 for the 5% most central collisions. The value of $\langle {\rm d}N_{\rm ch}/{\rm d}η\rangle$ normalised to $\langle N_{\mathrm{part}}\rangle/2$ as a function of $\sqrt{s_{\mathrm{NN}}}$ follows the trend established in previous measurements in heavy-ion collisions. Theoretical models based on mechanisms for particle production in nuclear collisions that involve the formation of quark-gluon plasma medium and models based on individual nucleon-nucleon interactions are compared to the data.

nucl-ex

Exploring the origin of D$^0$ meson elliptic flow in PbPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV using event shape engineering

The influence of the initial-state geometry on the elliptic flow of prompt D$^0$ mesons in high-energy heavy ion collisions is explored. A lead-lead (PbPb) data sample at a center-of-mass energy per nucleon pair of 5.02 TeV and with an integrated luminosity of 0.607 nb$^{-1}$ was collected in 2018 with the CMS detector at the CERN LHC. Based on these data, an event-shape engineering technique is used to isolate collisions with similar geometrical properties. An asymmetry parameter, $q_2$, is first determined from the distribution of transverse energy in the forward region of the detector. This parameter is shown to be linearly correlated with the elliptic anisotropy of inclusive charged particles measured near mid-rapidity, as characterized by the second-order Fourier coefficients, $v_2$. Taking the charged particle $v_2$ coefficients as proxies for the initial-state eccentricity, the correlation of D$^0$ meson $v_2$ values near mid-rapidity with those of inclusive charged particles is then studied. For D$^0$ mesons with transverse momenta in the range of 2$-$30 GeV and for different degrees of collision overlap, the $v_2$ values are found strongly correlated with those for charged particles when selected based on similar $q_2$ intervals. This correlation suggests that the initial-state geometry substantially impacts the development of charm-hadron flow in heavy ion collisions. A model calculation that explores the thermalization and collective motion of D$^0$ mesons and charged particles is compared to the experimental results.

nucl-ex

Evidence for sequential $Υ$(nS) suppression in light ion collisions

Bound states of heavy quark-antiquark pairs, known as quarkonia, have long been regarded as particularly sensitive probes of the quark-gluon plasma (QGP). Comparing quarkonium yields in collisions of heavy nuclei, such as gold or lead, with a proton-proton (pp) reference reveals a characteristic pattern of sequential suppression, in which weakly-bound excited states are more strongly suppressed than the ground states. We report the first measurements of the three lowest mass $\mathrm{S}$-wave vector bottomonium resonances, the ground state $Υ$(1S) and the excited states $Υ$(2S) and $Υ$(3S), in oxygen-oxygen collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_\mathrm{NN}}$ = 5.36 TeV. Measurements of the yields of the $Υ$(1S) and $Υ$(2S) resonances in neon-neon collisions, at the same $\sqrt{s_\mathrm{NN}}$, are also presented. The $Υ$(2S)/$Υ$(1S) ratio is found to be significantly below the measured pp reference value, and the $Υ$(3S)/$Υ$(1S) ratio shows an even larger reduction. The significance of the relative $Υ$(3S) to $Υ$(2S) suppression exceeds three standard deviations. These results provide evidence for the sequential suppression of $Υ$(nS) states in light ion collisions, similar to observations made in lead-lead and gold-gold collisions, generally attributed to the presence of a QGP medium.

nucl-ex