arXiv subjects
Publications and source records attributed to Sheldon Stone.
We describe a method that provides a model independent measurement of the Bs fraction in Y(5S) resonance decays, fs, using the relative rates of like-sign versus opposite sign dileptons; the like-sign leptons result from B^0 and Bs mixing. In addition, we show that determining the rates of single, double and triple Ds mesons provides an alternative way of finding fs.
Heavy, as yet undiscovered particles, can affect measurements of CP violation in the B system. Measuring CP violation in the Bs system provides an excellent place to observe such effects since Standard Model sources are predicted to produce very small effects. The angle -2beta_s, the "phase of Bs-\bar{B}s mixing," thought to be best measured in Bs -> J/psiϕdecays is of order -0.04, while the CP violating asymmetry in Bs -> ϕϕis predicted to be zero, due to the cancellation of the mixing phase with the decay phase. Recent measurements of β_s in J/psiϕ, while not definitive, are much larger than the Standard Model predictions. Measurements in the B^o and Ds+ systems of analogous modes point toward a 5-10% contamination of S-wave K+K- under the ϕpeak. This S-wave was not taken into account in these recent analyses. Furthermore this S-wave can also materialize as a f0(980) meson that decays to π+π-, making the final state J/psi f0 useful for measuring β_s with the added advantage of not requiring an angular analysis. Rate estimates, while not precise, predict four to five times fewer such events than those in the J/psiϕmode. The error on β_s, however, may be similar. We also remark on S-wave problems with the Bs -> ϕϕmode, and possible systematic checks using Bs -> ϕf0.
We update our previous results by increasing the luminosity, the efficiency, and for the Ds+ the number of tags. We determine f{D+}=(205.8 +/- 8.5 +/- 2.5) MeV, and an interim preliminary value of f{Ds+}=(267.9 +/- 8.2 +/- 3.9) MeV, where both results are radiatively corrected. We agree with the recent most precise unquenched Lattice-QCD calculation for the D+, but are in disagreement for the Ds+. Several consequences are discussed, including the possibility of physics beyond the Standard Model.
We review here the physics of purely leptonic decays of pi-, K-, D+, Ds+, and B- pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak interaction based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and anti-quark wave-functions in the meson, called the decay constant fP. The interplay between theory and experiment is different for each particle. Theoretical predictions that are necessary in the B sector can be tested, for example, in the charm sector. One such measurement, that of fDs, differs from the most precise unquenched lattice calculation and may indicate the presence of new intermediate particles, or the theoretical prediction could be misleading. The lighter pi and K mesons provide stringent comparisons due to the accuracy of both the measurements and the theoretical predictions. This review was prepared for the Particle Data Group's 2008 edition.
I report final CLEO-c results on the purely leptonic decays of the D_s^+ -> l^+ nu, for the cases when l^+ is a mu^+ or tau^+, when it decays into pi^+ anti-nu, using 314/pb of data at 4.170 GeV. I also include preliminary results from the tau^+ -> e^+ nu anti-nu channel using 195/pb. Combining both we measure f_{D_s}= 275 +/- 10 +/- 5 MeV, and f_{D_s^+}/{f_{D^+}=1.24 +/- 0.10 =/- 0.03 .
Using the CLEO III detector, we measure absolute cross sections for e+e- -> hadrons at seven center-of-mass energies between 6.964 and 10.538 GeV. R, the ratio of hadronic and muon pair production cross sections, is measured at these energies with a r.m.s. error <2% allowing determinations of the strong coupling alpha_s. Using the expected evolution of alpha_s with energy we find alpha_s(M_Z^2)=0.126 +/- 0.005 ^{+0.015}_{-0.011}, and Lambda=0.31^{+0.09+0.29}_{-0.08-0.21}.
I report preliminary CLEO-c results on purely leptonic decays of the Ds using 195/pb of data at 4.170 GeV. We measure fDs = 280.1 +/- 11.6 +/- 6.0 MeV, and fDs/fD+ = 1.26 +/- 0.11 +/- 0.03.
I discuss new results on absolute branching ratios of charm mesons into specific exclusive final states, Cabibbo suppressed decay rates, inclusive decays to $s\bar{s}$ mesons, limits on D^0 anti-D^0 mixing, CP violation and T violation. Preliminary results from CLEO-c now dominate the world average absolute branching fractions. For the most important normalization modes involving D^0 and D^+, the averages are B(D^0 -> K^- pi^+ = (3.87 +/- 0.06)%, and B(D^+ -> K^- pi^+ pi^+)= (9.12 +/- 0.19)%. For the Ds^+ CLEO-c measures B(Ds+ -> K^- K^+ pi^+)=(4.54^{+0.44}_{-0.42} =/- 0.25)%. Using this rate, I derive an effective branching ratio B(eff)(Ds^+ -> phi pi^+)=(3.49 +/- 0.39)%, that is appropriate for use in extracting other branching fractions that have often been measured relative to this mode. This number is compared with other determinations.
A short summary is given of the current status of B physics. Reasons for physics beyond the Standard Model are discussed. Constraints on New Physics are given using measurements of B mixing, Bs mixing, and CP violation, along with |Vub. Future goals, and upcoming new experiments are also mentioned.
The interplay of experiment and theory is explored in the context of current data on b and c decay. Measurements of |Vcb| and |Vub| are extracted from existing data. Conservative estimates give |Vcb|=(42.4 +/- 1.2{exp} +/- 2.3{thy})x10^{-3} and |Vub|=(3.90 +/- 0.16{exp} +/- 0.53{thy})x10^{-3}. Using these values along with data on Bd, Bs mixing and CP violation in the K_{Long} system, the allowed region of the CKM parameters rho and eta is derived. Tests of factorization in two-body hadronic B decays to one heavy and one light meson are shown and compared with modern theories which are also used to see if there is new physics in two-body B decays to light mesons. The two new narrow D_{sJ} states, discovered by BaBar and CLEO, respectively, are interpreted in light of the observation of these states in B decays by Belle.
Using 13.5 inverse-femtobarns of e+e- annihilation data in the CLEO II detector at CESR, we have observed a new narrow state decaying to Ds*+ pio, denoted the DsJ(2463). A possible interpretation holds that this is a J^P = 1+^ partner to the DsJ*(2317) state recently discovered by the BaBar Collaboration which is consistent with J^P = 0^+. We have also confirmed the existence of the DsJ*(2317) in its decay to Ds+ pio. We have measured the masses of both states, accounting for the cross-feed background that the two states represent for each other, and have searched for other decay channels for both states. No narrow resonances are seen in neutral or doubly charged Ds pi modes.
Many topics are discussed in b physics including lifetimes, decay mechanisms, determinations of the CKM matrix elements |V_{cb}| and |V_{ub}|, facilities for b quark studies, neutral $B$ meson mixing, rare b decays, hadronic decays and CP violation. I review techniques for finding physics beyond the Standard Model and describe the complimentarity of b decay measurements in elucidating new physics that could be found at higher energy machines.
I discuss how b decays can be used to unravel new physics beyond the Standard Model. Decays second order in the weak interaction involving loops and CP violation are emphasized. This information is complementary to that obtainable with higher energy machines.
I discuss some key issues covered at the Conference including physics goals, current results on CKM angles, rare decays, status of $|V_{cb}|$ and $|V_{ub}|$, CKM fits and progress on hardware.
I discuss examples of what Dr. Irving Langmuir, a Nobel prize winner in Chemistry, called "the science of things that aren't so." Some of his examples are reviewed and others from High Energy Physics are added. It is hoped that discussing these incidents will help us develop an understanding of some potential pitfalls.
Recent results include the measurement of B->D(*)pi+pi-pi-pi0 decays, with rates of ~1.8% observation of a significant omega pi^- substructure that appears to result from the decay of the rho' resonance, whose mass and width we determine as 1418 MeV and 382 MeV, respectively. Using B to charmonium decays we find that the neutral B fraction in Y(4S) decays is nearly half, that the CP asymmetries in J/ψK^(-/+) and psi' K^(-/+) are small, and we also report on the first observation of B->eta_c K.
Many measurements are necessary in the program of studying mixing, CP violation and rare decays of b and c quarks. These measurements require large numbers of B^o, B_s, B^- and D^{*+} hadrons. Fortunately, copius production of particles containing b and c quarks will occur at Tevatron and the LHC. The crucial measurements are described here, as well as the design of the two experiments, LHC-b and BTeV, that can exploit the 4-20 x 10^{11} b hadrons produced every 10^7 seconds.
I discuss what measurements need to be done to search for physics beyond the Standard CKM model, rather than just what studies can be done in the near future. It is also important to accurately measure the CKM matrix elements. Current best estimates for two important elements are: |V_{cb}|=0.0381 +/- 0.0021 and |V_{ub}/V_{cb}|=0.085 +/- 0.019. Finally, future experiments are discussed.