Welcome to the web pages of the UNH Nuclear and Particle Physics Group, which is part of the Physics Department. The group is located in our new building, the rebuilt DeMeritt Hall. The Nuclear Physics Group’s (NPG) research is aimed at two primary areas of study:

  1. Searches for physics beyond the Standard Model;
  2. Understanding the structure of the nucleon and light nuclei, and how this can be described in terms of the strong interaction and spin degrees of freedom.

These mission goals map to two of the top science questions for the 21st century: “What is Dark Matter?”  and “What is the missing spin of the nucleon?” 

We lead several multi-national collaborations at Jefferson Lab, and are preparing for several additional experiments at this facility. Jefferson Lab is presently completing a $314M upgrade, which was highlighted as the top priority of the last NSAC (National Science Advisory Committee) report. There are four full time faculty (Maurik Holtrop, Elena Long, Nathaly Karl Slifer). Two postdoctoral research scientists and six graduate students  work in the NPG on Jefferson Lab projects. Over the past decade we have mentored nine PhDs, and more than twenty undergraduates. These students make significant contributions to our efforts both at UNH and at Jefferson Lab, where they work side by side with some of the top scientists in the field. Our main experimental efforts are:

  • The Heavy Photon Search (spokesperson: Holtrop) searches for a new gauge boson –the heavy photon– as a potential particle in a hidden sector that could also contain the Dark Matter.
  • The g2p experiment (spokesperson: Slifer) investigates the spin structure of the proton and how this affects the energy levels of hydrogen like systems.
  • The Isospin SRC experiment (spokesperson: Solvignon, Slifer) used a tritium target to probe how short-range correlations between nucleons affect the structure of nuclei.
  • The Tensor Spin Observables program at Jefferson Lab uses a novel tensor polarized solid target to measure observables that are impossible to measure without tensor polarization. The b1 experiment (spokespersons: Slifer, Long, Santiesteban) recently recieved full approval from Jefferson Lab PAC51, as did the Azz experiment (spokespersons: Long, Santiesteban, Slifer) to measure the tensor asymmetry in the x>1 region.

The NPG has a major research initiatives in DeMeritt Hall. The group is establishing a cryogenically cooled solid polarized target lab in DeMeritt Hall 103 in support of the Tensor Spin Observables program. We recently installed our new 7 Tesla superconducting solenoid which provides the target holding field. This project is a collaboration with the University of Virginia and Jefferson Lab polarized target groups.

UNH Physics Colloquium – Friday September 22

Speaker: Josh Pierce

Institution:  Oak Ridge National Laboratory

Title: Group leader, HFIR Low Temperature and Magnets group

Website: https://www.ornl.gov/staff-profile/josh-j-pierce

Date: 09/22/2023

Title: Dynamic Nuclear Polarization for Neutron Crystallography

Protein crystallography is an established technique for determining the structure of many protein systems. X-ray protein crystallography is the dominant technique, as the incredibly high flux of modern light sources allows researchers to collect data very quickly using very small crystals. In comparison, neutron crystallography has many unique advantages (due the neutron’s sensitivity to isotopes and light nuclei) but suffers from the low flux available at neutron sources. The spin dependence of slow neutron scattering provides an opportunity to overcome the flux limitations of neutron sources, expanding the number of protein systems that can be studied, improving the signal to noise, and enabling novel measurement techniques to determine the location of hydrogen atoms. At Oak Ridge National Laboratory, a program has been underway to develop Dynamic Nuclear Polarization (DNP) techniques, and apply them to neutron scattering.  A brief background on neutron sources and scattering will be presented, along with a description of Dynamic Nuclear Polarization, results of tests at ORNL, and plans for a future DNP enhanced diffractometer being designed for construction at the High Flux Isotope Reactor (HFIR).


Nathaly Santiesteban

UNH NPG welcomes a new faculty member

Dr. Sandra Nathaly Santiesteban has joined the Physics Department and the Nuclear and Particle Physics Group at UNH in the Fall of 2022. She has an active and growing research program at Jefferson Lab, which centers on studies of the nucleus, specifically investigating Short Range Correlations and spin.