Welcome to CHEP seminars

Recent Seminars at the Centre for High Energy Physics are listed here

RECENT SEMINARS

07.03.2012

4.00 pm

Lec. Hall - 3
Physical Science
Building
High transverse momentum quarkonium production and dissociation in heavy ion collisions.
Speaker:  Rishi Sharma
Affiliation: Fermi National Laboratory, Illinois.
Abstract:
Melting of heavy quarkonium states like the J/\psi and the Upsilon mesons due to color screening in a deconfined quark-gluon plasma (QGP) has been proposed as one of the principal signatures for its formation. An expected experimental consequence of this melting  in the thermal medium created in heavy-ion collisions (HIC) is a suppression of the yield of heavy mesons, when compared to their yield in nucleon-nucleon (NN) collisions scaled with the number of binary interactions.  I will describe a calculation of the yields of quarkonia in heavy ion collisions at RHIC and the LHC as a function of the transverse momentum based upon heavy quark effective theory. Included is a consistent implementation of dynamically calculated nuclear matter effects, such as coherent power corrections, cold nuclear matter energy loss, and the Cronin effect in the initial state and collisional dissociation of quarkonia in the final state as they traverse through the QGP. I will compare the results with data where applicable. The large suppression of prompt J/\psi  in nucleus-nucleus collisions at the LHC might indicate for the first time a possible thermal modification of the quarkonium wavefunction at large transverse momentum.

slides of lecture
08.03.2012

4.00 pm

Lec. Hall - 3
Physical Science
Building
Thermoelectric probe for neutral edge modes in the fractional quantum Hall regime
Speaker:  Dr. Sourin Das
Affiliation:  University of Delhi
Abstract :
The \nu = 5/2 anti-Pfaffian state and the \nu = 2/3 Abelian state are believed to have an edge state composed of counter-propagating charge and neutral edge modes. This situation allows the generation of a pure thermal bias between two composite edge states across a quantum point contact (QPC) as was experimentally established in Nature 466, 585 (2010). We show that replacing the QPC by a quantum dot provides a natural way for detecting the neutral modes via the finite current generated by the thermoelectric response of the dot. We also show that the degeneracies of the dot spectrum, dictated by the conformal field theories (CFTs) describing these states, induce asymmetries in the thermoelectric current peaks. This in turn provides a direct fingerprint of the corresponding CFT manifested in a different shape of peaks patterns for the two quantum Hall states.

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slides of lecture

Our news
06.03.12
Lectures on Helicity Amplitudes
Prof. S. Rindani's Lectures have been postponed indefinitely