Wed·Oct 10, 2018Wednesday·October 10, 2018

1. 01*

   Inclusive Studies of Short-Range Correlations: Overview and New Results

   Zhihong Ye🇺🇸 · John Arrington🇺🇸

   We present an overview of Short-Range Correlations (SRC) studies using the inclusive measurement of the electron scattering off nuclei. A brief introduction of the origin of the SRC is given, followed by the survey of the two-nucleon SRC (2N-SRC) study and its interesting connection to the EMC effect. A discussion of the three-nucleon SRC study (3N-SRC) measured by the Jefferson Lab's Hall B and Hall C experiments which showed contradictory results is given and, most importantly, we report a new result from the Hall A E08-014 experiment which was dedicated on studying 3N-SRC. Our high precision 4He/3He cross section ratios at the x > 2 region do not show a 3N-SRC plateau as predicted by the naive SRC model. To further investigate the 3N-SRC as well as the Isospin effect of the SRC, we have designed several approved experiments in Hall A and in Hall C, including the Tritium experiments using the mirror nuclei (3H and 3He) which are currently running in Hall A.

   nucl-exhep-phnucl-th9 citations
2. 02*

   Worldwide Search for the Neutron EDM

   B. W. Filippone🇺🇸

   Existing limits on the electric dipole moment (EDM) of the free neutron have provided critical constraints on new sources of CP violation for more than 60 years. A new round of searches are actively underway with the goal of improving the sensitivity to CP violation by up to two orders-of-magnitude. The status of these new searches will be discussed, including recent progress on the nEDM experiment to be carried out at the Fundamental Neutron Physics Beamline at the Oak Ridge National Laboratory's Spallation Neutron Source.

   nucl-exphysics.ins-det14 citations
3. 03*

   PHENIX study of the initial state with forward hadron measurements in 200 GeV p(d)+A and ${}^3$He$+$Au collisions

   Jason Bryslawskyj (for the PHENIX Collaboration)🇺🇸

   Forward hadron measurements in p(d)+A provide a signal to study nuclear shadowing, initial state energy loss and/or gluon saturation effects as a function of rapidity, centrality and energy. High $p_T$ identified ${\pi }^0$ measurements are an essential first step toward measuring prompt photon production. The ${\pi }^0$ measurements are enabled by the PHENIX MPC-EX detector, a Si-W preshower detector located in front of the Muon Piston Calorimeter (MPC), expanding the neutral pion reconstruction capabilities in the rapidity range $3.1<\eta <3.8$ out to high energies, $E<80$ GeV. Previous PHENIX measurements of punch-through charged hadrons in the muon arms in the rapidity range $1.4<|\eta |<2.2$ were significantly improved through the capability of the forward silicon vertex detector (FVTX) to determine the transverse momentum and rapidity with high precision and reject background from secondary hadrons. PHENIX collected d+Au data with the MPC-EX in the 2016 run at $\sqrt{s_{NN}}=$ 200, 62, 39 and 19.6 GeV; and p+p and p+Au(Al) data with the FVTX in 2015 at 200 GeV. In this talk, we will present first results for high $p_T$ ${\pi }^0$ production from the $\sqrt{s_{NN}}$ = 200 GeV dataset, the status of the prompt photon measurement, as well as charged hadron nuclear modification factors in p+Au(Al) and ${}^3$He$+$Au.

   nucl-exNPA(2019)·1 citation
4. 04*

   Direct photon elliptic flow in Pb-Pb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=2.76$ TeV

   Mike Sas (for the ALICE collaboration)🇳🇱

   The elliptic flow of inclusive and direct photons was measured by ALICE for central and semi-central Pb--Pb collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}=2.76$ TeV. The photons were reconstructed using the electromagnetic calorimeter PHOS and the central tracking system. The inclusive photon flow reconstructed with both methods are combined and used to extract the direct photon flow, using a decay photon simulation and the direct photon excess R${}_{\gamma }$, in the transverse momentum range $0.9<p_{\mathrm{T}}<6.2$ GeV/c. We find agreement to earlier results obtained at RHIC, and the theoretical predictions generally under-predict the results.

   nucl-exNPA(2019)·1 citation
5. 05*

   Productions of $f_1(1420)$ in pion and kaon induced reactions

   Xiao-Yun Wang🇨🇳 · Jun He🇨🇳 · Quanjin Wang🇨🇳 · Hao Xu🇨🇳

   The $f_1(1420)$ productions via pion and kaon induced reactions on a proton target are investigated in an effective Lagrangian approach. Two treatments of the $t$-channel Born term, the Feynman model and the Regge model, are introduced to calculate the total and differential cross sections of the ${\pi }^{-}p\to f_1(1420)n$ and $K^{-}p\to f_1(1420)\Lambda$ reactions. The numerical results indicate that the experimental data of the total cross section of the ${\pi }^{-}p\to f_1(1420)n$ reaction can be reproduced in both the Feynman and the Regge models. Based on the parameters determined in the pion induced reaction, the cross sections of the $K^{-}p\to f_1(1420)\Lambda$ reaction, about which there is little data found in the literature, are predicted in the same beam momentum range. It is found that the line shapes of the total cross section obtained in a kaon induced reaction with two treatments are quite different. The cross sections for both reactions are at an order of magnitude of $\mu$b, or larger, at a beam momenta up to 10 GeV/c. The differential cross sections for both pion and kaon induced reactions are also present. It is found that in the Regge model, the $t$ channel provides a sharp increase at extreme forward angles. The results suggest that the experimental study of the $f_1(1420)$ in the kaon induced reaction on a proton target is as promising as in the pion induced reaction. Such an experimental measurement is also very helpful to clarify the production mechanism of the $f_1(1420)$.

   ↳ hep-phnucl-exnucl-thPRD(2019)·8 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.