The field of theoretical high-energy physics has progressed enormously during the last 40 years. We have an extremely accurate theory, the Standard Model, that explains all current data. There are indications, however, that it is not the most fundamental description of nature. The UCR theory group studies modifications and extensions of the Standard Model in the hope of providing a yet more fundamental description of nature.
The particle identity of 85% of the matter in the universe is a mystery.
How does it interact with ordinary matter, and does it interact in novel ways
with itself? UCR has been a driving force in developing new models for
dark matter and identifying novel ways to search for their characteristic
signatures. The search for dark matter draws together incorporates all types
of particle physics, from colliders, to undergrond low-background environments,
to space telescopes, and even to observations of the early universe.
The emerging field of astro-particle physics is a new frontier where we may use
stars and galaxies as laboratories for fundamental physics. Recent theoretical
and numerical advances now allow us to probe the unique role that dark matter
plays in the formation of galaxies. Astronomical observations can thus
illuminate features of the dark sector that are inaccessible to terrestrial
Precision measurements in cosmology are also a recent frontier in particle
physics. Undiscovered particles beyond the Standard Model can be important
components of the 'cosmic soup' in the early universe. They can leave indelible
imprints in the cosmic microwave background or be key players in baryogenesis,
the origin of matter.
The origin of neutrino mass remains one of the open questions of the
Standard Model. Ongoing and upcoming experiments will pin down important
features of the neutrino mass heirarchy and CP phase. This will help
shape the theory of neutrino flavor symmetries and connections to
hidden sectors of nature.
Supersymmetry and Extra Dimensions
Two of the benchmark frameworks for new physics are supersymmetry and
extra dimensions. Supersymmetry unifies force-particles and matter-particles
in a way that can explain the apparent lightness of the Higgs mass. By the
holographic principle, extra dimensions are widely understood to be
duals of strongly coupled four-dimensional theories. They help us understand
scenarios where the Higgs is itself a composite particle.
Searches for New Physics
In addition to large, general purpose colliders such as
the Large Hadron Collider, and specialized experiments such as those for
dark matter (in)direct detection; UCR physicists have found ways to repurpose
exisiting experiments in novel ways to search for new phenomena. These include
searching for new particles from the sun using the IceCube neutrino experiment,
or searching for new, weakly-coupled particles in nuclear decays.
Numerical Astro-Particle Simulations
Cosmology and the nature of dark matter can be studied in the non-linear regime
by means of high resolution numerical simulations. We use supercomputers and a
combination of different codes with the aim of modeling the formation of dark matter
halos and larger structures in the Universe, making different assumptions regarding the cosmology and/or
the nature of dark matter. Our group has experience in running and analyzing large
simulations within the preferred LCDM model, but also exploring alternative models
of dark matter, such as warm dark matter or self-interacting dark matter.
Collaborations and Networks
We work closely with colleagues from the astronomy group.
Recent topics of collaboration have focused on the role of self-interacting dark matter in
structure formation in the early universe. Numerical simulations of galaxy evolution
combined with observations of distant systems now allow us to test predictions of
dark matter self-interactions.
The SoCal DM Network (UCSD, UCLA, UCI, UCR) focuses on exploiting new the capabilities in numerical modeling of baryonic feedback on structure for constraining and probing ideas on dark sector physics, and then pulling in new observations and new calculations of dark matter particle physics in the early universe and in stars and compact objects.
We host regular meetings for the Southern California theoretical particle
physics / beyond the Standard Model community. Our goal is to facilitate collaboration between
the broad expertise in the range of particle phenomenology covered by our research groups.