-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathresearch.html
executable file
·169 lines (130 loc) · 10.2 KB
/
research.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
---
layout: default
---
<a id="research"></a><h1>Research</h1>
<p>
The group has broad research interests across nuclear physics, with a
particular speciality being applications of lattice QCD to
contemporary problems.
</p>
<hr>
<p>
<b>Dudek's</b> research interests lie principally in understanding the
<b>spectrum of excited hadrons</b> within QCD. While the traditional
picture of hadrons has mesons as $q\bar{q}$ bound-states and baryons
as $qqq$, QCD in principle allows for a much richer spectrum, which
might include states constructed from larger numbers of quarks, or
hadrons featuring only glue (glueballs) or quarks and glue
(hybrids). </br>
Complicating matters is the fact that excited hadrons are unstable
states, <i>resonances</i>, which can decay into lighter, stable
hadrons, and the dynamics which binds quarks and gluons into hadrons is the same dynamics which controls their decay — both must be
studied simultaneously.</br>
Dudek is interested in application of lattice QCD to problems
in hadron spectroscopy, and past calculations by Dudek and his
collaborators appear to show, as well as the expected $q\bar{q}$-like mesons
and $qqq$-like baryons, also the presence of hybrid mesons and
baryons. The resonant nature of excited states can be studied through their
appearance in <i>scattering amplitudes</i>, which can be extracted
from lattice QCD calculations by utilizing the dependence of the
lattice spectrum on the size of the 'box' defined by the lattice
boundary. Dudek performs research on these topics within the <b><a href="https://www.hadspec.org">
hadspec collaboration</a></b>.
</p>
<hr>
<!-- <p>
<b>Monahan's</b> work uses lattice QCD to study the <b>internal structure
of hadrons, their weak interactions and in searches for new physics at
the precision frontier</b>. One strand of his research focuses on how
quarks and gluons are arranged inside protons and neutrons,
information that can be used at the LHC to reduce background
uncertainties in searches for new particles. </br>
A second strand focuses on determining the interactions of heavy hadrons, containing b quarks, with the weak nuclear force. These interactions are central to constraining the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix, which describes how quarks mix under the weak interaction. The CKM matrix is unitary in the Standard Model of particle physics, so any signs of non-unitarity could hint at the presence of unknown physics at high energies. </br>
In addition, Monahan's research interests include the close interplay between the quantum field theory techniques used in lattice QCD and statistical physics, which describes the behavior of large systems of particles. In particular, Monahan studies thermal Casimir effects in fluids, which are the statistical analog of the famous electromagnetic Casimir force between two conducting plates.
</p> -->
<p>
<b>Jackura's</b> research program focuses on the study of <b>few-body nuclear and particle reactions</b> to probe the emergence of the excited hadron spectrum from QCD. The program uses tools and techniques from both lattice QCD and reaction theory to construct a pipeline from first principles calculations of hadrons from QCD dynamics to their scattering amplitudes. </br>
Jackura's work includes developing theoretical frameworks for amplitude analyses, phenomenological studies of hadronic production processes, and numerical calculations using lattice QCD. At the forefront of this program is the investigation of the relativistic quantum three-body problem and the study of electroweak probes of hadronic systems. </br>
Jackura is a member of the <b><a href="https://www.hadspec.org">hadspec collaboration</a></b>, a group specializing in using high-performance super computers to study hadron reactions and QCD spectroscopy. He is also a member of <b><a href="https://www.exohad.org">ExoHad</a></b>, a collaboration which explores all aspects of exotic hadron physics, and <b><a href="https://www.jpac-physics.org">JPAC</a></b> -- a group of theorists, phenomenologists, and experimentalists who work together to provide analysis tools for hadron spectroscopy.
</p>
<hr>
<p>
<b>Orginos's</b> research
focuses on understanding the physics of hadrons, whose
dynamics is governed by the strong interactions. Quantum
Chromodynamics (QCD), the theory of strong interactions, has a
remarkably rich phenomenology. Because the interaction becomes strong
at low energies, Lattice QCD is the only known way to compute
rigorously the properties and interactions of hadrons directly from
QCD. In recent years, substantial progress has been made in the field,
providing us with the opportunity to compute many observables of
central importance in subatomic physics. Using Lattice QCD Orginos is
currently studying low energy hadronic phenomenology, including the
<b>structure and interactions of hadrons, weak interactions, and
fundamental symmetries</b>. In addition, he works on developing new
computational techniques that make possible the study of phenomena
currently inaccessible to available computational resources.
Orginos's current research interests include <i>hadron interactions,
hadron structure, algorithms for lattice field theory and other
topics in computational physics</i>.
</p>
<hr>
<p>
Emeritus Professor <b>Carlson</b> works on a variety of topics, mainly on the theme on using <b>precision nuclear or particle physics to find discrepancies from standard-model physics</b>, with a significant subinterest in optics and atomic physics, currently targeted on phenomena related to twisted photon states. Nuclear physics topics include two-photon physics to explain discrepancies between different ways of measuring the proton charge form factor, early-on-neglected corrections to the proton weak charge measurement that turned out to be larger than the anticipated experimental uncertainty, and corrections relevant to and possible beyond the standard model explanations of the proton radius puzzle. Regarding twisted photons, they are photon states of large intrinsic angular momentum, which can on atomic or nuclear targets induce quantum number changes impossible for plane wave photons. Far future applications include using energetic twisted photons to isolate high spin baryon or nuclear excited states. Currently we are successfully testing ideas by studying twisted photon phenomena in an atomic context.
</br>
</p>
<hr>
<p>
The determination of the three-dimensional structure of hadrons in
terms of the fundamental quark and gluon (or parton) degrees of
freedom of QCD is one of the outstanding challenges of the Standard
Model and a central mission of the Jefferson Lab science program. The
<b>Jefferson Lab Theory Center</b> plays a leading role in the development of
new formalisms and techniques to quantify this structure through
various quantum correlation functions, such as parton distribution
functions (PDFs), fragmentation functions (FFs), transverse momentum
dependent distributions (TMDs), generalized parton distributions
(GPDs), and multi-parton correlation functions. Opportunities for
Ph.D. research in these areas are available at Jefferson Lab through
<i>Governor’s Distinguished CEBAF Professor Qiu and Adjunct Professors Melnitchouk and Richards</i>.</br></br>
In particular, the research of <b>Qiu</b> focuses on the theory and phenomenology of QCD to identify and develop factorization formalisms to match experimentally measured cross sections at Jefferson Lab and worldwide, as well as what can be calculated in lattice QCD, to the quantum correlation functions of quarks and gluons, and to extract these correlation functions from experimentally measured and lattice QCD calculated data.</br></br>
The research of <b>Melnitchouk</b>, through the Jefferson Lab Angular Momentum (JAM) and CTEQ-JLab (CJ) collaborations, utilizes state-of-the-art analysis techniques, including Bayesian inference, Monte Carlo sampling, and machine learning, to extract the quantum correlation functions from experimental high-energy scattering data.
</p>
<!--
<p>
<b>Shanahan's</b> research interests lie in understanding the
emergence of the complexity of <b>hadron and nuclear structure</b>
from the Standard Model of particle physics. Shanahan combines
analytic methods such as effective field theories and supercomputer
calculations on discrete spacetimes (lattice QCD) to solve the complex
equations of quantum chromodynamics (QCD) and quantum electrodynamics
(QED). Recently, she has been working on novel applications of machine
learning techniques to this problem. </br></br>
Working towards a ground-up understanding of nuclear physics,
Shanahan, Orginos and collaborators have performed the first
first-principles theoretical calculation of the matrix element
dictating the proton-proton fusion cross-section, which is the
reaction that provides the dominant energy production mechanism in
stars like the Sun. They also achieved direct calculations of
double-beta decay matrix elements for the first time, revealing a
previously neglected and potentially significant contribution to these
processes. These calculations, and future refinements to fully control
all systematic uncertainties, will be invaluable to the interpretation
of the results of significant existing and planned experimental
programs searching for evidence of the Majorana nature of neutrinos. </br></br>
Shanahan has recently established a program to determine, for the
first time, quantities which describe the gluonic structure of light
nuclei. This structure provides a window to the intriguing phenomenon
of confinement and the emergence of complex structure in Nature. While
very few aspects of gluonic structure have been determined
experimentally at the present time, an Electron-Ion Collider designed
with the specific aim of performing first measurements of many gluonic
structure quantities is the highest priority for new construction in
the long-range plan of the nuclear physics community. This program is
currently in the planning phase, with data-taking anticipated within
the next decade. Recent results include the first indication that the
gluon structure of light nuclei is not simply that of a
non-interacting collection of nucleons—that is, the first indication
of ‘exotic’ nuclear glue effects. </br></br>
</p>
-->