arXiv subjects

Karl Slifer

Publications and source records attributed to Karl Slifer.

5 recordsLinked to original sources

arXiv2025

Spin 1 Transverse Momentum Dependent Tensor Structure Functions in CLAS12

We propose to analyze CLAS12 RG-C data to study the tensor transverse-momentum-dependent parton distribution functions (TMDs) on deuteron data. The deuteron is the lightest nucleus with spin-1, in essence a weakly bound system of two spin-1/2 nucleons. However, one of the most intriguing characteristics of the deuteron is that the tensor polarized structure provides direct access to the quark and gluon distribution of light nuclear system, which cannot be naively constructed from the proton and neutron. We will study the tensor polarized structure functions with the Semi-inclusive Deep Inelastic Scattering (SIDIS) $eD \arrow eP_{h}X$ and Inclusive processes in the available data on deuterated ammonia (ND3) target. We will perform the first ever SIDIS analysis extraction of the tensor structure functions, which can be interpreted in term of completely unexplored tensor polarized TMDs. Our analysis will focus on the extraction of the tensor structure functions b1 from inclusive process, and $F_{U(LL),T}$ and $F^{cos 2\phi_{h}}_{U(LL)}$ from SIDIS. These last two structure functions carry information related to two tensor-polarized TMDs, $f_{1LL}$ and $h^{\perp}_{1LL}$. These initial exploratory measurements of tensor-polarized structure functions will enable the first extraction of spin-1 TMDs and motivate more precise future measurements.

hep-ph↗

arXiv2024

New Spin Structure Constraints on Hyperfine Splitting and Proton Size

The 1S hyperfine splitting in hydrogen is measured to an impressive ppt precision and will soon be measured to ppm precision in muonic hydrogen. The latter measurement will rely on theoretical predictions, which are limited by knowledge of the proton polarizability effect $\Delta_\text{pol}$. Data-driven evaluations of $\Delta_\text{pol}$ have long been in significant tension with baryon chiral perturbation theory. Here we present improved results for $\Delta_\text{pol}$ driven by new spin structure data, reducing the long-standing tension between theory and experiment and halving the dominating uncertainty in hyperfine splitting calculations.

nucl-ex↗

arXiv2015

Beam Position Reconstruction for the g2p Experiment in Hall A at Jefferson Lab

Beam-line equipment was upgraded for experiment E08-027 (g2p) in Hall A at Jefferson Lab. Two beam position monitors (BPMs) were necessary to measure the beam position and angle at the target. A new BPM receiver was designed and built to handle the low beam currents (50-100 nA) used for this experiment. Two new super-harps were installed for calibrating the BPMs. In addition to the existing fast raster system, a slow raster system was installed. Before and during the experiment, these new devices were tested and debugged, and their performance was also evaluated. In order to achieve the required accuracy (1-2 mm in position and 1-2 mrad in angle at the target location), the data of the BPMs and harps were carefully analyzed, as well as reconstructing the beam position and angle event by event at the target location. The calculated beam position will be used in the data analysis to accurately determine the kinematics for each event.

physics.ins-det↗

arXiv2013

Novel Physics With Tensor Polarized Targets

The Jefferson Lab PAC recently approved an experiment which will use an enhanced tensor po- larized solid target. This exciting development holds the potential of initiating a new field of tensor spin physics at JLab. Experiments which utilize tensor polarized targets can help clarify how nuclear properties arise from partonic degrees of freedom, provide unique insight into short range correlations and quark angular momentum, and help pin down the polarization of the quark sea.

nucl-ex↗

arXiv2013

Dynamically polarized target for the g2p and GEp experiments at Jefferson Lab

We describe a dynamically polarized target that has been utilized for two electron scattering experiments in Hall A at Jefferson Lab. The primary components of the target are a new, high cooling power 4He evaporation refrigerator, and a re-purposed, superconducting split-coil magnet. It has been used to polarize protons in irradiated NH3 at a temperature of 1 K and at fields of 2.5 and 5.0 Tesla. The performance of the target material in the electron beam under these conditions will be discussed. Maximum polarizations of 28% and 95% were obtained at those fields, respectively. To satisfy the requirements of both experiments, the magnet had to be routinely rotated between angles of 0, 6, and 90 degrees with respect to the incident electron beam. This was accomplished using a new rotating vacuum seal which permits rotations to be performed in only a few minutes.

physics.ins-det↗