Biomedical subjects

Aneesh V Manohar

Publications and source records attributed to Aneesh V Manohar.

5 recordsLinked to original sources

PubMed2004

Baryon exotics in the quark model, the skyrme model, and QCD.

We derive the quantum numbers of baryon exotics in the quark model and the Skyrme model and show that they agree for arbitrary colors and flavors. We define exoticness E, which can be used to classify the states. The exotic baryons include the recently discovered qqqqq pentaquarks (E=1), as well as exotic baryons with additional qq pairs (E>/=1). The mass formula for nonexotic and exotic baryons is given as an expansion in 1/N(c) and allows one to relate the moment of inertia of the Skyrme soliton to the mass of a constituent quark.

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PubMed2003

Enhanced nonperturbative effects in jet distributions.

We consider the triple differential distribution d Gamma/dE(J)dm(2)(J)d Omega(J) for two-jet events at center of mass energy M, smeared over the end-point region m(2)(J)<<M2, absolute value 2E(J)-M approximately Delta, Lambda(QCD)<<Delta<<M. The leading nonperturbative correction, suppressed by Lambda(QCD)/Delta, is given by the matrix element of a single operator. A similar analysis is performed for three-jet events, and the generalization to any number of jets is discussed. At order Lambda(QCD)/Delta, nonperturbative effects in four or more jet events are completely determined in terms of two matrix elements which can be measured in two- and three-jet events.

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PubMed2003

Isospin violation in e+ e- -->BB.

The ratio of the B+ B- and B0B0 production rates in e+ e- annihilation is computed as a function of the B meson velocity and BB*pi coupling constant, using a nonrelativistic effective field theory.

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PubMed2002

Delta-->Ngamma in large-N(c) QCD.

The decay Delta(+)-->pgamma is studied in the 1/N(c) expansion of QCD. The ratio of the helicity amplitudes is determined to be A(3/2)/A(1/2)=sqrt[3]+O(1/N(2)(c)). Equivalently, the ratio E2/M1 of the multipole amplitudes is predicted to be order 1/N(2)(c).

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PubMed2002

Spontaneously broken spacetime symmetries and Goldstone's theorem.

Goldstone's theorem states that there is a massless mode for each broken symmetry generator. It has been known for a long time that the naive generalization of this counting fails to give the correct number of massless modes for spontaneously broken spacetime symmetries. We explain how to get the right count of massless modes in the general case, and discuss examples involving spontaneously broken Poincaré and conformal invariance.

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