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<b>The group will leave from the CEBAF Center front door at 9:50
a.m. to walk over to the TED Building. There is a sidewalk that
runs along the west wall of the EEL building and is the best way
to get to the TED.
</b><br>
<br>
<br>
Theory Center Seminar<br>
Friday, Feb. 5, 2016<br>
10:00 a.m. (coffee at 9:45 a.m.)<br>
TED Bldg., Room 2561 A&B<br>
<br>
<div class="moz-forward-container"> Phiala Shanahan<br>
MIT<br>
<br>
<b>Strange and Charge Symmetry Violating Electromagnetic Form
Factors of the Nucleon from Lattice QCD</b><br>
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<br>
Since strange quark contributions to nucleon observables must arise
entirely through interactions with the vacuum, their sign and
magnitude provide key information regarding the nonperturbative
structure of the nucleon. Understanding this structure is a grand
challenge for nuclear physics and a central focus of research at
Jefferson Lab. At the present time, the dominant uncertainty in the
experimental numbers for the strange proton form factors arises from
the assumption of good charge symmetry which informs their
extraction. In fact, with theoretical predictions of the size of
charge symmetry violation (CSV) varying through several orders of
magnitude, this uncertainty (along with the remarkable experimental
challenges) has halted certain aspects of experimental
parity-violating electron scattering programs. In this seminar I
will describe the use of dynamical 2 + 1-flavor lattice QCD
simulation results for the electromagnetic form factors of the octet
baryons, together with effective field theory methods, to determine
both the strange and CSV form factors of the nucleon to an
unprecedented level of precision. In addition, I will present my
vision for my research program which will center around the role of
hidden flavors and gluons in both hadron and nuclear structure, as
well as the 3D spatial and momentum tomography of the nucleon, from
lattice QCD. The calculation of gluon observables in the deuteron
will make contact with experiments proposed in a JLab letter of
intent, while studies of hidden flavor in nuclei will tie in with
the ATHENNA experiment. There has recently been significant
technical progress which makes the lattice calculation of GPDs and
TMDs, which are a focus of the JLab 12GeV research program, an
achievable goal. <br>
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