Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the branching ratios of the Cabibbo-suppressed decay modesD0 → π−π+ and D0 → K−K+. We measured: Γ(D0 → K−K+)/Γ(D0 → π−π+) = 2.81 ± 0.10(stat) ± 0.06(syst), Γ(D0 → K−K+)/Γ(D0 → K−π+) = 0.0993 ± 0.0014(stat) ± 0.0014(syst), and Γ(D0 → π−π+)/Γ(D0 → K−π+) = 0.0353 ± 0.0012(stat) ± 0.0006(syst). These values ha...

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the branching ratios of the Cabibbo-suppressed decay modesD0 → π−π+ and D0 → K−K+. We measured: Γ(D0 → K−K+)/Γ(D0 → π−π+) = 2.81 ± 0.10(stat) ± 0.06(syst), Γ(D0 → K−K+)/Γ(D0 → K−π+) = 0.0993 ± 0.0014(stat) ± 0.0014(syst), and Γ(D0 → π−π+)/Γ(D0 → K−π+) = 0.0353 ± 0.0012(stat) ± 0.0006(syst). These values ha...

It is often said that the only constant is change itself. As time passes, the population grows, new technologies are invented, and the skills, demographics, and norms of the populace evolve. These changes, whether in isolation or in aggregate, impact the effectiveness of policy. In particular, policies designed for today’s world are unlikely to provide a perfect fit tomorrow. In this paper we d...

We report the first observation of B → ηX transitions with high momentum η mesons. We observe 39.0 ± 11.6 B decay events with 2.0 < pη′ < 2.7 GeV/c, the high momentum region where background from b → c processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to b → sg transitions. Given that interpretation, we find B(B → ηXs) = (6.2...

According to our present understanding many J/c production processes proceed through a colored cc̄ state followed by the emission of soft particles in the quarkonium rest frame. The kinematic effect of soft particle emission is usually a higher-order effect in the non-relativistic expansion, but becomes important near the kinematic end point of quarkonium energy ~momentum! distributions. In an i...

The googly amplitudes in gauge theory are computed by using the off shell MHV vertices with the newly proposed rules of Cachazo, Svrcek and Witten. The result is in agreement with the previously well-known results. In particular we also obtain a simple result for the all negative but one positive helicity amplitude when one of the external line is off shell.

In this contribution, we introduce higher spin Dirac operators, i.e. a specific class of differential operators in Clifford analysis of several vector variables, motivated by equations from theoretical physics. In particular, the higher spin Dirac operator in three vector variables will be explicitly constructed, starting from a description of the so-called twisted Rarita-Schwinger operator.

Efforts to predict the rare exclusive decay B → Kγ from the well known inclusive decay b → sγ are frustrated by the effect of the large recoil momentum. We show how to reduce the large uncertainty in calculating this decay by relating B → Kγ to the semileptonic process B → ρeν̄ using the heavy-quark symmetry in B decays and SU(3) flavor symmetry. A direct measurement of the q-spectrum for the se...