CP-violation and mixing in charmed mesons

The Standard Model contribution to D0-anti-D0 mixing is dominated by the contributions of light s and d quarks. Neglecting the tiny effects due to b quark, both mass and lifetime differences vanish in the limit of SU(3)_F symmetry. Thus, the main challenge in the Standard Model calculation of the mass and width difference in the D0-anti-D0 system is to estimate the size of SU(3) breaking effects. We prove that D meson mixing occurs in the Standard Model only at second order in SU(3) violation. We consider the possibility that phase space effects may be the dominant source of SU(3) breaking. We find that y=(\Delta \Gamma)/(2\Gamma) of the order of one percent is natural in the Standard Model, potentially reducing the sensitivity to new physics of measurements of D meson mixing. We also discuss the possibility of observing lifetime differences and CP violation in charmed mesons both at the currently operating and proposed facilities.Comment: 13 pages, no figures, invited talk at Continuous Advances in QCD 2002 / ARKADYFEST, May 17-23, 200

The use of neutrino beams from muon storage rings

I give a brief overview of the physics potential of short baseline experiments at neutrino factories, i.e. facilities providing high energy and high intensity neutrino beams, like the one planned to be built in connection with the proposed high energy muon storage ring. These facilities would offer a unique opportunity to perform new precision studies of QCD and electroweak interactions. New types of measurements, such as studies of gluon density of the nucleon via charmonium production and extractions of V_cb and V_ub CKM matrix elements, will become possible. Interesting new physics scenarios can also be explored.Comment: 8 pages, no figures, based on invited talks given at 23rd Johns Hopkins Workshop on Current Problems in Particle Theory: Neutrinos in the Next Millennium, Baltimore, MD, 10-12 June 1999, and The International Conference on Physics Potential and Development of mu+ mu- Colliders, San Francisco, CA, 15-17 December 199

Dipenguin-like contributions to D0 - anti-D0 mixing

We show that because of the milder GIM suppression, the four-quark dipenguin operator contributes to the short distance piece of the D^0-\bar D^0 mixing amplitude at the same order of magnitude as the box diagram. In addition, we put an upper bound \Delta m_D^{LDR} \leq 5 \times \Delta m_D^{box} on a long-distance resonant contribution induced by the penguin mixing.Comment: 4 pages, 1 figure; to appear in the proceedings of HADRON'97, BNL, August 1997; preprint number is adde

Lifetimes of heavy hadrons

We review current status of theoretical predictions of lifetimes of heavy hadrons in heavy-quark expansion. We present a calculation of subleading 1/m_b corrections to spectator effects in the ratios of beauty hadron lifetimes. We find that these effects are sizable and should be taken into account in systematic analyses of heavy hadron lifetimes. In particular, the inclusion of 1/m_b corrections brings into agreement the theoretical predictions and experimental observations of the ratio of lifetimes of Lambda_b-baryon and B_d meson. We obtain \tau(B_u)/\tau(B_d) = 1.09 \pm 0.03, \tau(B_s)/\tau(B_d)= 1.00 \pm 0.01, \tau(\Lambda_b)/\tau(B_d)= 0.87 \pm 0.05.Comment: 10 pages, 4 figures. Invited talk at the workshop `Continuous Advances in QCD 2004', Minneapolis, Minnesota, May 13-16 200