A recent recepient of the JSA Promising Young Scientist Award and the JSA Post Doctoral Research Prize, Elena is researching the ways that a tensor-polarized target can be utilized to understand nuclear effects. Currently, she is 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.
Elena is also the lead spokesperson on an approved experiment to do the first measurement on the quasi-elastic tensor asymmetry Azz. 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 neucleon methods, as well as provide new experimental constraints on decades-old quetsions about the S/D ratio of deuteron wavefunctions.
Her dissertation measured asymmetries that tested models used to extract the neutron form factors. Many extractions are done with plane wave impulse approximaion (PWIA), which predicts an asymmetry (Ay0) of vertically polarized 3He(e,e'n) to be exactly zero. Non-zero asymmetry is indicative of final state interactions, meson exchange currents, and other effects beyond PWIA. She also obtained 3He(e,e'n) asymmetries with the target polarized longitudinal to a polarized electron beam from which the magnetic form factor of the neutron (GMn) can be extracted and with the target polarized transverse to a polarized electron beam and parallel to the q-vector from which the electric form factor of the neutron (GEn) can be extracted.
The video below is from a Google Hangout Seminar that was hosted by the University of Central Arkansas, in which Dr. Long gives an overview of her field and ends with her recent work on electron scattering from tensor polarized deuterons.
Along with her research, Elena has been working on creating resources for people in physics. In 2014, she was elected to the Jefferson Lab User's Group Board of Directors to represent the needs of Post-Docs associated with the lab. In 2009, she founded an organization, LGBT+ Physicists, that has grown to include networking opportunites, an OutList, and is continuing to make physics better for the LGBT+ people in the field. She is also the Vice President of Diversity and Inclusion for oSTEM, Inc. where she has been working towards making the STEM fields more accessible to LGBT+ undergraduate and graduate students.
Approved Experiment Proposals
E12-15-005: Measurements of the Quasi-Elastic and Elastic Deuteron Tensor Asymmetries (Lead Spokesperson)
E12-13-011: The Deuteron Tensor Structure Function b1 (Spokesperson)
E12-11-008: A Proposal for the DarkLight Experiment at the Jefferson Laboratory Free Electron Laser
Letter of Intent
LOI12-14-002: Tensor Asymmetry Azz in the x>1 Region (Contact Spokesperson)
Y. X. Zhao, et al., Double spin asymmetries of inclusive hadron electroproduction from a transversely polarized 3He target, Phys. Rev. C 92 015207 (2015)
N. Ackerman, T. Atherton, W. Deconick, M. Falk, S. Garmon, E. Henry, E. Long, Gender and Sexual Diversity Issues in Physics: The Audience Speaks, arXiv:1206.4112v1 (2012)
J. Huang, et al., Beam-Target Double Spin Asymmetry ALT in Charged Pion Production from Deep Inelastic Scattering on a Transversely Polarized 3He Target at 1.4 < Q^2 < 2.7 GeV2, Phys. Rev. Lett. 108, 052001 (2012)