CDF @ IFAE

Institut de Física d'Altes Energies

Fermilab is a High Energy Physics Laboratory located 45 miles west of Chicago, Illinois, USA. It hosts the Tevatron, the most energetic proton-antiproton collider operational in the world, with a center-of-mass energy of 1.96 TeV. The collisions are studied by two first-class experiments, CDF & D0. The CDF experiment is formed by an international collaboration of about 800 researchers from 62 different institutions. After the discovery of the quark top in 1995 both the accelerator and the detectors have peformed major upgrades. Since February 2002, when the "Run II" officially started, the experiments are collecting high-quality physics data and presenting the results in conferences.

For Run II the Tevatron has been upgraded with a new main injector and a new anti-proton recycler. The energy has been increased from 1.8 to 1.96 TeV. The machine has already reached a record instantaneous luminosity of 3.7 10^32 cm-2 s-1 (summer 2010) and delivered more than 8000 pb-1 of data.

The CDF II detector is a multi-purpose detector designed for physics studies at the Tevatron. It will allow to probe distances of 10^-19 meters and look for quark sub-structure, perform precise studies of the quark top, establish oscillations in the Bs system, search for the SM HIggs boson, search for supersymmetry and physics processes beyond the standard model, and much more...

The IFAE Group in CDF

In 2003 and 2004, the IFAE group defined a research program based on the study of events with jets of hadrons in the final state, and multi-jet events with large missing transverse energy as a signature for new phenomena and in particular super-symmetry. These studies have led to 2 PhD Theses in 2007 and 1 PhD Thesis and 1 Master Thesis in 2008. Two additional PhD Theses are expected in 2009. In addition, the IFAE group in CDF has major responsibilities on quality monitoring (DQM) of the data used by CDF for physics analyses.

Inclusive Jet Production.
In Run II, the measurement of the inclusive jet cross section is a fundamental piece of the Tevatron physics program. Thanks to the increase in the centre-of-mass energy, the jet cross section has increased by a factor about 3 compared to Run I for jets with transverse energies above 500 GeV and the new measurements extend the kinematics region of the transverse energy of the jets up to values of about 700 GeV (corresponding to distances of the order of 10^-19 m). Final results, for central and forward jets, and using up to 1fb-1 of Run II data, have been published in Physical Review Letters and Physical Review D.
Search for Supersymmetry (Squarks andf Gluinos).
The search for new physics beyond the standard model and, in particular, supersymmetry, is one of the main goals of both the Tevatron and the LHC physics programs. At the Tevatron, the best sensitivity to the production of supersymmetric particles comes from the study of hadronic final states with multiple jets and large missing transverse energy. These topologies could correspond to the production of squarks and gluinos which decay producing cascades of gluons and quarks, which are detected as multiple jets in the final state. For those models where R-parity is conserved, the LSPs (Lightest Supersymmetric Particles) are considered stable and leave CDF undetected, producing a signal of large missing transverse energy. The results extend Run I exclusion limits on squark and gluino masses significantly and have been published in Physical Review Letters.
Search for Supersymmetry (Sbottom pair production).
In MSSM, for high values of tan, the large mass splitting in the third generation sector yields to low masses for the lightest sbottom state. If R-parity is conserved, sbottoms are expected to be produced in pairs via gg fusion or qqbar annihilation. The sbottom is forced to decay into bottom and the lightest neutralino (assumed to be the LSP), leading to final states which include two b-jets and substantial missing transverse energy (MET). An analysis searching for sbottom-pair production has been carried out and results are published in Physical Review Letters.
Study of Z+jet Events.
In 2005, the group opened a new line of analysis with detailed studies of jet production in events with a Z boson in the final state. Precise measurements on Z+jets production constitute a fundamental test of pQCD and provide a clean sample to validate Monte Carlo predictions for background estimations in searches for new physics. Measured cross sections have been compared to pQCD NLO predictions and published in Physical Review Letters. The analysis continues with more data..
Inclusive Prompt Photon Production.
During 2007 and 2008 members of IFAE in collaboration with the Fermilab Group have carried out a new measurement of the prompt photon cross section. The measurement of isolated high pt photons in the final state is sensitive to the presence of new physics like, for example, Gauge Mediated SUSY breaking, as well us provides information on the gluon distribution in the proton via the dominant production process with a gluon in the initial state. The measurements have been compared with NLO pQCD predictions and no signal of new physics have been observed. The results were submitted to Physical Review D Rapid Communications for publication.
DQ for CDF.
The quality control is performed at two levels. Online, an automatic system alerts the CDF shift crew if faults are observed in the data. The online system is based on JAVA monitors that control the basic performance of the detector. The online diagnosis is available via Web and finally kept in ORACLE databases. Offline, after the data has been processed, a DQM system automatically checks the quality of the data using very high level physics objects (electrons, photons, muons, J/Psi, jets, etc) which, in addition to confirming the online diagnosis, detects possible errors introduced in the offline reconstruction codes or calibration constants. The final DQM decisions are employed to establish standard good run lists for the whole collaboration.

Part of the IFAE Group at Fermilab/CDF (Fall 2007)

Members of the IFAE Group in CDF (as on Summer 2010)

M. Cavalli-Sforza (Research Professor)
M. Martinez (ICREA Research Professor)
S. Grinstein (ICREA Researcher)
V. Sorin (Research Associate, RyC)
Gianluca De Lorenzo (PhD Student)
Stefano Camarda (Phd Student)
Lorenzo Ortolan (PhD Student)

IFAE at Fermilab's Result of the Week

Selected Physics Resuls from the Group

Selected Talks in Conferences from the Group (2006-2009)

Former IFAE-CDF Members
Monica D'Onofrio (now with permanent position in Liverpool University), Regis Lefevre (now Staff Reseach Scientist at Clermont-Ferrand, France), Olga Norniella (now Research Fellow at Illionis-Urbana, USA), Xavier Portell (now Research Fellow at Freiburg, Germany), Carolina Deluca (now Research Fellow at SUNY, USA), Carlos Sanchez (now at X-Ray Project @ IFAE), O. Salto (now in Industry), A. Attal (now in Industry).

CDF @ IFAE webpage

Last Modified: 1 Oct 2009 (M. Martinez)