[Jlab-seminars] Today's Physics Seminar: Axel Schmidt; The SRC-EMC Connection

[Stephanie Tysor]

Physics Seminar
Axel Schmidt
Massachusetts Institute of Technology

The SRC-EMC Connection

Abstract:


The EMC Effect, the observation that quark momentum distributions in nuclei are substantially different from those of free protons and neutrons, has eluded a definitive explanation for over 35 years and remains one of the large open questions in nuclear physics. The fact that quarks and gluons, with GeV-scale dynamics, are affected by the MeV-scale nuclear environment, may point the way to learning something profound about nuclei, or even confinement itself. While several explanations for the EMC Effect have been ruled out by experiment, two broad classes of explanations remain. In one, the EMC Effect comes about from the attractive mean-field, leading to a modest modification to the structure of all nucleons. In the other, the SRC-EMC hypothesis, most nucleons are un-modified, but those in short-range correlated (SRC) pairs change their structure dramatically.

In a recent paper, I and my collaborators presented new data from CLAS and developed a phenomenological model that lends strong support to the SRC-EMC hypothesis. Our analysis is the first simultaneous extraction of the EMC effect and the SRC pair density in carbon, aluminum, iron, and lead. Our model shows that the universal modification of only SRC nucleons can explain the world EMC Effect data, and has numerous applications, such as the extraction of the free neutron structure function.

The SRC-EMC hypothesis will be tested experimentally using a technique called ``Recoil-tagged deep inelastic scattering." The current BAND experiment (Hall B) and upcoming LAD experiment (Hall C) will make a definitive statement about the role SRC pairs play in the EMC Effect.



Friday, April 5, 2019
11:00am
CEBAF Center Auditorium



Stephanie Tysor
Thomas Jefferson National Accelerator Facility
Physics Division
Hall A Administrative Assistant
(office)757-269-6005<callto:757-269-6005> (fax)757-269-5235<callto:757-269-5235>

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