arXiv subjects

Richard Haas

Publications and source records attributed to Richard Haas.

3 recordsLinked to original sources

arXiv2000

Search for Susy with Missing Transverse Energy and Jets at CDF

Events with signatures involving large missing transverse energy (MET) are among the quintessential search modes for R-parity conserving supersymmetry. CDF has conducted two recent analyses for supersymmetry which use MET and jets. The MET and monojet signature is employed to determine process independent limits for the production of new physics beyond the Standard Model and then applied to models of spontaneous breaking of supersymmetry to determine limits on the supersymmetry breaking parameter and the gravitino mass. Direct searches for scalar top and scalar bottom quarks within the framework of supersymmetric models are performed using a signature of MET and two heavy flavor jets. Since the data is found to be consistent with Standard Model expectations, limits are determined in the mass planes $m (\tildeχ_{1}^{0}) - m (\tilde{t}_{1})$ and $m (\tildeχ_{1}^{0}) - m (\tilde{b}_{1})$.

hep-ex↗

arXiv2000

Search for Second and Third Generation Leptoquarks at CDF

We report the results of a search for second and third generation leptoquarks using 88 ${pb}^{-1}$ of data recorded by the Collider Detector at Fermilab. Color triplet technipions, which play the role of scalar leptoquarks, are investigated due to their potential production in decays of strongly coupled color octet technirhos. Events with a signature of two heavy flavor jets and missing energy may indicate the decay of a second (third) generation leptoquark to a charm (bottom) quark and a neutrino. As the data is found to be consistent with Standard Model expectations, mass limits are determined.

hep-ex↗

arXiv1996

Oscillons in a Hot Heat Bath

In models of real scalar fields with degenerate double-well potentials, spherically symmetric, large amplitude fluctuations away from the vacuum are unstable. Neglecting interactions with an external environment, the evolution of such configurations may entail the development of an oscillon; a localized, non-singular, time-dependent configuration which is {\it extremely} long-lived. In the present study we investigate numerically how the coupling to a heat bath influences the evolution of collapsing bubbles. We show that the existence and lifetime of the oscillon stage is extremely sensitive to how strongly the field is coupled to the heat bath. By modeling the coupling through a Markovian Langevin equation with viscosity coefficient $γ$, we find that for $γ\gtrsim 5 \times 10^{-4}m$, where $m$ is the typical mass scale in the model, oscillons are not observed.

hep-ph↗