Theoretical, T

T-2 Particle Physics

Collective oscillations: Importance of anisotropy
Alex Friedland, Joe Carlson

Modeling collective oscillations in a supernova is often done in the "single-angle" approximation: neglect anisotropy of the problemWe have recently discovered that this approximation fails for realistic late-time spectra
The full problem is highly computationally demanding: thousands of energy and angular bins -> millions of coupled rays Domain of supercomputing!

Complicated pattern of collective oscillations in energy-angle space
from H. Duan and A. Friedland

Supernova Neutrinos
Collective oscillations: three-flavor effects

In a SN, ν’s are dense enough to affect each other’s flavor evolution. The whole ensemble evolves collectively
An intrinsically nonlinear phenomenon, with many surprises
Neutrino oscillations are usually treated in a 2-flavor framework. For solar, atmospheric, beam, and reactor neutrinos this is justified.
In a SN, however, the 2-flavor description breaks down spectacularly


Understanding different physical regimes of collective flavor oscillations

We have recently found that collective oscillations have different physical regimes, depending on the fluxes and spectra of emitted neutrinos
This finding has implications for the design of future detectors at DUSEL (P-division connection), as well as for the nucleosynthesis calculations (intersection of several PNAC disciplines)
We are collaborating with several institutions on this work: UNM, NCSU, UCSD, U. of Minnesota

Jet Substructure:
Example processes (MSSM but not limited to):

• boosted gluinos, boosted Higgs

• jets + missing energy challenging for discovery: large background Z+jets, W+jets

Isoptropic distributions are difficult to study

Boosted gluinos (e.g. from squrk decay) result in "fat jets", a lot of substructure, planarity signatures
Potential for discovery now!

A boosted provides features – fat jets, substructure


Very Challengin – featureless


Box Pectrum: gluino mas 405 GeV, squark mass 1000 TeV Lowest order production cross-section at 7 TeV COM:
gluino-gluino 3.9 pb, gluino-squark with squark > quark + gluino 0.77 pb


Discovering and Probing New Phsyics at the LHC
Important Questions:
1. How do we demonstrate that a "new physics" discovery is indeed due to new physics and not Standard Model processes?

2. what is its mass?
3. what are its couplings and interactions?

For 1: using jet substructure to impove dicovery potential of new physics (I. Shoemaker) and validate disvoery using tools of effective field theory (G. Ovanesyan) (20110098ER)

For 3: using a charge assymmetry to infer interactions of new matter to quarks and leptons


The High Energy Frontier of Nuclear and Particle Physics
contact Michael Graesser an Ivan Vitev

Significance: Top priority for nuclear (NSAC) and particle phsyics (P5);
important implications for cosmology (direct dark matter detection)

Timeliness: Colliders that push the limits of particle and nculear phsyics and now in operation – pressing need for novel theoretical tools


New Physics at the TeV scale:
origin of mass, supersymmetry, extra dimension, dark matter, ...


New Physics at the GeV scale:
new states-of-matter, unexpected properties, new partice interactions in matter, ...


T-2 Focus Areas




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