Selected Papers

This directory contains descriptons and links to some of the physics that I have worked on.

CMS: Hadron Collider Physics at the LHC

The Higgs discovery was announced on July 4, 2012. We lead one of the diphoton analyses, the Vector-Boson Fusion. In this mode, the proton proton collision produces Higgs particles by emitting W+W- bosons that interact to produce a Higgs. In the Standard Model, the rates for VBF are lower than the rates for general (glue-glue) production of the Higgs.
However, VBF opens a window on the electroweak symmetry breaking (why the Higgs was postulated in the first place, decades ago).
Our VBF result, submitted to JHEP, is here .

The 3jet resonance search we invented at CDF (see below) was also done at CMS. The large rates at the LHC mean that jet thresholds have to be set high, and therefore we could not search for the top excess we saw at CDF
(UPDATE: this is being addressed with special triggers in the 2012 run!)
The first CMS result came out with 2010 data in PRL (Physical Review Letters).
The result with 2011 data is being prepared for publication now, the public results are here .

A sophisticated multilepton search for new physics we did here at Rutgers with a large group has been accepted by JHEP . This analysis does not make any model-dependent selections, so is sensitive to most models of new physics that have leptons (Supersymmetry, 4th generation quarks, etc).

CDF: Hadron Collider Physics at the Tevatron

We invented an entirely new technique to look for multi-jet resonances. With this technique we were able to see top quarks decay to 3 jets, without any additional kinematic requirements (like b-jets, W-resonance, leptons).
In other words, if you didn't already know that there was supposed to be a resonance at 175 GeV/c^2, this would have been one way to find it.
The paper was published in PRL .
Note that there was an excess of top quarks in this analysis. We did additional studies with more data. We looked for the signal of the W-boson within the top and found that the excess was indeed due to top quarks, and not some other 3jet resonance at similar mass.
Extra Plots for the multijet top excess.

On CDF we have performed one of the most sensitive searches for the MSSM Higgs Boson, published in Physical Review Letters in 2006.
We searched for Higgs decaying to tau leptons , and in the process greatly improved the status of tau physics at CDF.
Our work was highlighted in talks by Pier Oddone, director of Fermilab, as one of the most promising analyses being performed at the Tevatron.
We have a HREF=""> website for this analysis, which includes our limit plots (one of which is also shown in the 2006 Particle Data Book) and plots showing expected sensitivity with higher luminosity.
We updated this result in 2009 in this PRL

KTeV: Fixed Target Physics with Neutral Kaon Beam

The first paper published by KTeV was on the search for the neutral SUSY hadron, the R0, consisting of a light gluino paired with a gluon. I performed a more sophisticated search presented at the International Conference for High Energy Physics (ICHEP' 98, or the "Rochester Conference") in Vancouver, which was published in early '99.
[DIR] R0 Papers Reference papers for the KTeV light gluino search.

The rare decay K_L-> e+e-mu+mu- was finally seen with high enough statistics. This decay is important for determining the CKM matrix element V_td (from K_L->mu+mu-) This paper is also now published.

We also made a measurement of the radiative widths on excited kaons (including several states never before measured). Simply put, the radiative width gives the likelihood of an excited state decaying by emitting a photon. In other words, we find out well the picture of the neutral kaon as a hydrogen-atom-like structure (albeit with strange and down quarks instead of electron and proton) holds up.

SLD: Polarized electron-positron collisions at the Z pole

My thesis was on the SLD measurement of ALR, and the 1996 publication of this measurement , as well as a previous (1994) paper (my thesis) , are available. A paper on all the polarized asymmetries is also available. Langacker and Erler have interpreted this and other precision electroweak data as limits on Standard Model Higgs.
(UPDATE: The Higgs was found! See CMS section above. The mass was well inside the window predicted 17 years earlier by electroweak precision measurements like this one).

The ALR measurement depended on the Compton Polarimeter, which was cross-checked with a Moller Polarimeter. An interesting effect (Levchuk effect) due to atomic electron effects was seen to bias Moller Polarimetry.

Amit &
Last modified: Wed Jul 11 18:44:21 EDT 2012