People

Maurik Holtrop

Professor

Maurik is one of the spokespersons of the Heavy Photon Search (HPS) experiment (E12-11-006) at Jefferson Lab. This experiment looks for a new gauge boson, the “heavy photon” or “dark photon”, which could be part of a hidden sector that also includes potential dark matter candidates. He is also a member of the CLAS and CLAS12 experiments, where he is a co-spokesperson for experiments E12-06-106, “Study of Color Transparency in Exclusive Vector Meson Electroproduction off Nuclei”, E12-06-117, “Quark Propagation and Hadron Formation”, E12-06-119, “Deeply Virtual Compton Scattering with CLAS at 11 GeV”, and E12-06-109, “The Longitudinal Spin Structure of the Nucleon”.

UNH profile · Heavy Photon Search

Karl Slifer

Professor

Karl's principal research area is the study of nucleon spin structure functions via inclusive scattering from polarized targets. He is a co-spokesperson on the E08-027 experiment at Jefferson Lab, which measured the proton g₂ structure function. He is also a co-spokesperson for the EG4 experiment deuteron run, which measured the proton and deuteron g₁ structure functions. Karl is one of the primary proponents of the study of tensor spin observables. The E12-13-011 experiment at JLab, for which he is a co-spokesperson, will study the deuteron tensor structure function b₁, and probe the tensor-polarized quark and antiquark distribution functions. He is a co-spokesperson on experiment E12-15-005, which received an A− rating and was conditionally approved, and will measure the tensor asymmetry A_zz in the x > 1 region, which will explore the nature of short-range correlations in nuclei.

Karl runs the dynamic polarized target lab at UNH, where he tests new techniques for polarizing frozen ammonia targets.

UNH profile · Polarized Target Lab

Elena Long

Assistant Professor

Dr. Elena Long joined physics at the University of New Hampshire as a postdoc in 2013 and joined the faculty as an Assistant Professor in 2017. A recipient of the JSA Promising Young Scientist Award and the JSA Postdoctoral Research Prize, Dr. Long is researching the ways that a tensor-polarized target can be utilized to understand nuclear effects with a focus on understanding how the quarks inside of protons and neutrons come together to form atomic nuclei.

Dr. Long is the lead spokesperson on an approved experiment at Jefferson Lab to do the first measurement of the quasi-elastic tensor asymmetry A_zz. By utilizing tensor polarization, which enhances the deuteron's D-state, and looking at kinematics in the x > 1 region, short range nuclear effects are enhanced. This experiment will provide insight into relativistic nucleon-nucleon calculations, such as light cone and virtual nucleon methods, as well as provide new experimental constraints on decades-old questions about the S/D ratio of deuteron wave functions.

She is also working on measuring the deuteron structure function b₁, which was approved as the Jefferson Lab experiment E12-13-011. The b₁ structure function only exists in tensor polarized, spin-1 particles. If the deuteron is a simple combination of a proton and neutron, b₁ is zero. All conventional models predict b₁ to be vanishingly small at 0.1 < x < 0.7. However, a previous measurement by HERMES showed a large measurement around x = 0.45 that's 2 sigma from zero. The current measurement looks to greatly improve the uncertainty in this range, as well as map out a possible sign change in b₁.

UNH Long Lab · UNH profile · Tensor experiments

Nathaly Santiesteban

Assistant Professor

Dr. Nathaly Santiesteban joined the physics faculty at the University of New Hampshire in 2022.

UNH profile · Polarized Target Lab