Search

We present the latest version 2.6 of FeynHiggs, a program for computing MSSM Higgs-boson masses and related observables, such as mixing angles, branching ratios, and couplings, including state-of-the-art higher-order contributions. Also described are several new features in FeynArts 3.4 and FormCalc 5.4 which are mostly spin-offs of the FeynHiggs development. [Copyright &y& Elsevier]

This paper describes the B-physics trigger strategies for the ATLAS and CMS experiments. The LHC will produce B events at an unprecedented rate allowing the possibility to study rare decays. Due to the high event rate at the LHC the trigger systems are required to be very selective, reducing the rate by about six orders of magnitude for recording. The B-trigger must be able to reject non-B background (only about one collision in a hundred will produce a pair) and select the B-decay channels of specific interest (often with low branching ratios). In addition the B-trigger must be flexible enough to cope with increasing luminosity during the period of LHC running. The different strategies used to achieve this flexibility are discussed in this paper. [Copyright &y& Elsevier]

This report summarizes the flavor tagging techniques developed at the CDF and DØ experiments. Flavor tagging involves identification of the B meson flavor at production, whether its constituent is a b quark or an anti-quark. quark flavor content and hence the decay products do not identify the B flavor content at production. It is crucial for measuring the oscillation frequency of neutral B mesons, both in the B 0 and system. The two experiments have developed their unique approaches to flavor tagging, using neural networks and likelihood methods to disentangle tracks from b decays from other tracks. This report discusses these techniques and the measurement of B 0 mixing as a means to calibrate the taggers. [Copyright &y& Elsevier]

Rare loop-induced decays are sensitive to new physics in many Standard Model extensions. In this paper we discuss the potential of the LHC experiments to study the radiative penguin decays and the electroweak penguin decays . The experimental strategies are presented. [Copyright &y& Elsevier]

As is well known, the rare B-decays and offer a profound probe into the effects of physics beyond the Standard Model (SM). While present experimental upper limits from the Tevatron are roughly a factor of twenty above the SM predictions, the LHC experiments will reach SM values after the first year of nominal LHC luminosity and will allow a measurement of the decay probability. The three LHC experiments, ATLAS, CMS and LHCb are preparing triggers, offline reconstruction algorithms and signal selection strategies for these measurements. In this paper, special attention is devoted to background composition, especially to topologically-similar rare exclusive and exotic decays. [Copyright &y& Elsevier]

The LHCb experiment has an exciting potential for charm physics studies. A dedicated trigger will provide 108 events per of flavour tagged decays, which will give unprecedented sensitivity in searches for mixing and CP violation. The same sample provides an invaluable calibration signal for the experiment''s performance, in particular that of the RICH detector. This programme will be described, and initial Monte Carlo studies presented. [Copyright &y& Elsevier]

We present the current status of the rare B decay searches , , , , and at the Tevatron. [Copyright &y& Elsevier]

Recent results on , ℓℓ, and ℓℓγ from B-factories are briefly reviewed. The first measurement of the B meson decay constant at Belle is also presented. [Copyright &y& Elsevier]

Radiative and electroweak penguin decays of B mesons are flavor-changing-neutral-current processes that provide powerful ways to test the Standard Model at the one-loop level, to search for the effects of new physics, and to extract Standard Model parameters such as CKM matrix elements and quark masses. The large data samples obtained by the B-factory experiments BaBar and Belle, together with an intensive theoretical effort, have led to significant progress towards understanding these rare decays. Recent experimental results include the measurements of the decays , the observation of decays (together with studies of the associated kinematic distributions), and improved measurements of the inclusive rate and photon energy spectrum. [Copyright &y& Elsevier]

We review and lifetime and branching ratio measurements from the CDF and DØ experiments from the Tevatron Run II. Using up to 1 fb−1 data samples per experiment, the lifetime in decays, the lifetime difference in and decays and the branching ratio in decays are reported. [Copyright &y& Elsevier]

We have measured the time-integrated charge asymmetries in dimuon events and semileptonic decays. These results are the most precise semileptonic charge asymmetries in B decays to date. We combine these results with measurements from the decay to determine the CP-violating phase . We find . [Copyright &y& Elsevier]

Experimental results for the pseudoscalar decay constants and are reviewed. Semileptonic form factor results from and decays are also reviewed. [Copyright &y& Elsevier]

Analysis of the angular distributions of the final products of the decay chain allows the determination of mixing parameters, in particular the width difference between the weak eigenstates, , which is at present not precisely measured. It also allows measurement of the CP-violating phase of the system, which is expected to be very small (0.03 rad) in the Standard Model, but might show large non-Standard-Model enhancements. The high production rate of mesons at the LHC will permit precise measurements of these quantities; the performance of the three LHC experiments which have a B physics programme (ATLAS, CMS and LHCb) will be presented. [Copyright &y& Elsevier]

In this paper we review the results of untagged decays from the CDF and DØ detectors at Fermilab, using integrated luminosities of 260 pb−1 and 1.0 fb−1, respectively. Through a study of the time-dependent angular distributions of the decay products of the and ϕ mesons, the even and odd CP components of the decay are separated, and thus the lifetime difference and the CP violating phase are measured. The results are consistent with Standard Model predictions within the measurement uncertainties. [Copyright &y& Elsevier]

The last two years have seen an impressive improvement in the determination of , especially from inclusive decays. The error on measured with inclusive decays was reduced from 18% (PDG 2004) to 8% (PDG 2006). This progress is a result of combined experimental and theoretical efforts. In this talk, the theoretical framework (BLNP) that enabled such progress is reviewed, as well as other approaches to an inclusive determination of (DGE, M X − q 2 etc.). The prospects of improving are discussed, addressing issues of weak annihilation, implications of leptonic B decays, and determination of with exclusive decays. [Copyright &y& Elsevier]

B– mixing involves three physical parameters: the magnitudes of the off-diagonal elements of the mass and decay matrices and their relative phase. These parameters are related to the mass and width differences between the mass eigenstates and to the CP asymmetry in flavour-specific decays, a fs. Introducing a new operator basis I present new, more precise theory predictions for the width differences in the and systems: in the Standard Model one finds and . Updates of the mass differences and and of and are also presented. I then discuss how various present and future measurements can be combined to constrain new physics. The extraction of a new CP phase from data on also profits from our new operator basis. Confronting our new formulae with DØ data we find that deviates from zero by 2σ. [Copyright &y& Elsevier]

We report the observation of oscillations using 1 fb−1 of data from collisions with the CDF II detector at the Fermilab Tevatron. We measure the probability, as a function of proper decay time, that the decays with the same, or opposite, flavor as its flavor at production, which is determined using opposite-side and same-side flavor identification methods. We find a signal consistent with oscillations, with a significance greater than 5σ. We measure . [Copyright &y& Elsevier]

One of the most promising ways to determine the angle γ of the CKM unitarity triangle is through measurement of the tree level processes . The LHCb collaboration has studied the potential of these decays employing the Atwood-Dunietz-Soni (ADS) and Dalitz methods, making use of a large sample of simulated data. For each method the expected sensitivities to the angle γ are presented in this report. [Copyright &y& Elsevier]

I present an overview of the experimental determination of from inclusive and exclusive B semileptonic decays. The overview will include an introduction to the close interaction between theory and experiment in the extraction of , as well as to some of the experimental techniques brought to bear in the measurements. [Copyright &y& Elsevier]

The potential of LHCb for the extraction of the CKM angle α using the analysis of the and decay modes has been extensively studied. The expected performances are presented in this document. [Copyright &y& Elsevier]

We present new CDF results on the branching fractions and time-integrated direct CP asymmetries for B 0 and decay modes into pairs of charmless charged hadrons (pions or kaons). The data-set for this update amounts to 1 fb−1 of collisions at a center of mass energy 1.96 TeV. We report the first observation of the mode and a measurement of its branching fraction and direct CP asymmetry. We also observe for the first time two charmless decays of the -baryon: and . [Copyright &y& Elsevier]

We summarize the status of the measurement of the unitarity triangle angle γ performed by the BaBar and Belle collaborations using Dalitz plot analyses of the three-body decay of the meson from the process. Future prospects at the B factories are given. [Copyright &y& Elsevier]

A short review of methods to determine the CKM unitarity triangle angle γ based on decays is given, along with a discussion of the related theoretical errors. [Copyright &y& Elsevier]

I briefly summarize the factorization approach to hadronic B decays emphasizing theoretical results that have become available recently. The discussion of its application to data is abridged, and only the determination of from time-dependent CP asymmetries is included in some detail. [Copyright &y& Elsevier]

The LHCb experiment will collect very large samples of B-mesons decaying to charmless two-body final states. The combined measurements of the and time-dependent CP asymmetries allow a determination of the unitarity triangle angle γ, under the assumption of U-spin flavour symmetry. We present the status of the LHCb simulated analysis of the charged two-body charmless modes. [Copyright &y& Elsevier]

The angle α of the Unitarity Triangle has been measured in the , , and decays by the BaBar and Belle experiments that are collecting data at the B–factories at SLAC and KEK. The doubling of the dataset expected in the next couple of years will further increase the precision of the measurements. [Copyright &y& Elsevier]

Recent measurements of the time-dependent CP asymmetry parameter from penguin-dominated decays at B-factories are briefly reviewed. [Copyright &y& Elsevier]

I briefly review the theoretical status of semileptonic and radiative B decays in 2005. [Copyright &y& Elsevier]

Abstract: In this talk, we present our recent work [1] on the decays in a combined framework of chiral perturbation theory and Large-N c QCD under the dominance of a minimal narrow resonance structure. The proposed description reproduces very well the experimental Br(K + → π0e+e−) and Br(Ks → π0e0e−). Predictions for the K → π μ+μ− modes are also obtained and we can conclude to the constructive type for the interference between the direct and indirect CP-violation amplitudes in KL → π0e+e−. [Copyright &y& Elsevier]

We have searched for neutrinoless τ lepton decays into one electron or niuon and two charged pion or kaon using a 158 fb−1 data sample collected with the Belle detector at the KEKB collider. Since the number of signal candidate events is compatible with the expected background, we set 90% confidence level upper limits on the branching fractions in the range (2.2 −15.5) × 10−7 for various decay modes where ℓ and h represent e or μ and or , respectively. [Copyright &y& Elsevier]

We here report on a search for lepton-flavor violating τ decays, , with a 153.8 fb−1 data recorded by the Belle detector at the KEKB asymmetric-energy collider. For each of the six decay modes, the observed yield is compatible with background and the 90% confidence level upper limits on the branching fraction are obtained as 0.13 −1.0 × 10-6 which are a factor of 9 to 74 times better than previous measurements. [Copyright &y& Elsevier]

Search for the Lepton Flavor Violation has a long history since the discovery of muon. The MEG experiment, a new experiment to search for the Lepton Flavor Violating decay , is approved and being build at the Paul Scherrer Institut, Switzerland. The status of preparations of the experiment, in particular, the liquid Xe scintillation gamma ray detector, is briefly described. [Copyright &y& Elsevier]

We have searched for decays that violate both lepton and baryon number using data collected by the Belle detector at the KEKB asymmetric collider. No signals are found in , , , and and we set upper limits on the branching fractions of , , , and at the 90% confidence level. [Copyright &y& Elsevier]

The results of searches for Lepton Flavour Violating (LFV) decays at the BaBar detector located on the PEP-II collider, using data collected at an energy of 10.58 GeV, are presented. Upper limits at 90% Confidence Level (CL) are established in the range for six modes using 91.5 fb −1 of data and in the range for fourteen modes using 221.4 fb −1 of data. The results are preliminary. [Copyright &y& Elsevier]

Tau lepton decays with open strangeness in the final state are measured with the Opal detector at LEP to determine the strange hadronic spectral function of the τ lepton and the mass of the strange quark. The decays , and with final states consisting of neutral and charged kaons and pions, have been studied. The invariant mass distribution of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including η mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the τ lepton. The moments of the spectral function which are important input parameters for theoretical analyses, are determined. From the CKM weighted difference of strange and non-strange spectral moments, the mass of the strange quark has been measured to be . Furthermore, the branching fractions and have been measured. [Copyright &y& Elsevier]

Various complications encountered in the process of attempting to extract the basic Standard Model parameters, m s and V us , from hadronic τ decay data are discussed. [Copyright &y& Elsevier]

We review recent work to determine the strange quark mass as well as the proposal to determine using hadronic τ decay data. The recent update of the strange spectral function by OPAL and their moments of the invariant mass distribution are employed. Our results are and . Our result is already competitive to the standard extraction of from decays and to the new proposals to determine it. The error on is dominated by experiment and will be eventually much improved by the B-factories hadronic τ data. Ultimately, a simultaneous fit to both and to a set of moments of the hadronic τ decays invariant mass distribution will provide one of the most accurate determinations of these Standard Model parameters. [Copyright &y& Elsevier]

Full LEP-I data collected by the ALEPH detector during 1991-1995 running are analyzed in order to measure the τ decay branching fractions and the hadronic spectral functions. The analysis follows the global method used in the published study based on 1991-1993 data, with several improvements, especially concerning the treatment of photons and ''s. Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to 327148 measured and identified τ decays. Preliminary values for the branching fractions are obtained for the 2 leptonic channels and 11 hadronic channels defined by their respective numbers of charged particles and ''s. Using previously published ALEPH results on final states with charged and neutral kaons, corrections are applied so that branching ratios for exclusive final states without kaons are derived. Some physics implications of the results are given, in particular concerning universality in the leptonic charged weak current, isospin invariance in decays, and the separation of vector and axial-vector components of the total hadronic rate. Spectral functions are obtained for the main exclusive channels and the total inclusive rate, with separation of the vector and axial-vector states. [Copyright &y& Elsevier]

I outline recent results using CLEO3 data involving the decay of the τ to three charged hadrons and a neutrino, as well as an investigation of the structure of the decay and the Wess-Zumino term in this decay. [Copyright &y& Elsevier]

A preliminary measurement of the branching fraction is made using 124.4 fb−1 of collision data provided by the PEP-II accelerator, operating primarily at , and recorded using the BaBar detector. We measure: . This result is the world''s most precise measurement of this branching fraction to date and is consistent with the world average. [Copyright &y& Elsevier]

A search for the decay of the τ lepton to seven charged pions and at most one was performed using the BABAR detector at the PEP-II collider. The analysis uses data recorded on and near the resonance between 1999 and 2003, a total of 124.3 fb −1. We observe 7 events with an expected background of 11.9 ± 2.2 events and calculate a preliminary upper limit of at 90 % CL. This is a significant improvement over the previous limit established by the CLEO Collaboration. [Copyright &y& Elsevier]

The and decays have been studied using the BaBar experiment at the PEP-II storage ring. Preliminary branching fractions are given for the and to the sub-channels and . A preliminary upper limit is given on the branching fraction for the mode. In addition a preliminary measurement of the branching fraction of the decay is presented. [Copyright &y& Elsevier]

Full LEP-1 data collected by the ALEPH detector during 1991–1995 running are analyzed in order to measure the r decay branching fractions. The analysis follows the global method used in the published study based on 1991–1993 data, with several improvements, especially concerning the treatment of photons and π0''s. Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to 327148 measured and identified τ decays. Preliminary values for the branching fractions are obtained for the 2 leptonic channels and 11 hadronic channels defined by their respective numbers of charged particles and π0s. Using previously published ALEPH results on final states with charged and neutral kaons, corrections are applied so that branching ratios for exclusive final states without kaons are derived. Some physics implications of the results are given, in particular concerning universality in the leptonic charged weak current, isospin invariance in al decays, and the separation of vector and axial-vector components of the total hadronic rate. [Copyright &y& Elsevier]

New (preliminary) results for the form factors relevant for the semileptonic decays of heavy pseudoscalar to a light vector meson are presented. In particular, we discuss the form factors for D → K* and B → π modes. [Copyright &y& Elsevier]

Theoretical issues in the determination of |Vub| from inclusive decays are discussed, with emphasis on optimized cuts in the (q2, mx) plane and the endpoint of the charged lepton spectrum. [Copyright &y& Elsevier]

We report our calculation of the heavy-light decay constants fB and fD on a 203 × 48 lattice at β = 5.2 with nf = 2 sea quarks by the fully 0(a)-improved Wilson fermion and heavy quarks in Fermilab formalism. We find that the B meson decay constants are consistent with those obtained with the NRQCD formalism. It is shown that the quark mass dependence almost cancels in the B/D ratio of the decay constant so that the systematic errors in the chiral extrapolation can be reduced. Taking the Grinstein ratio, remaining uncertainties from the perturbation and discretization also cancel to give a precise prediction of SHAPE="SOL" ALIGN="C" STYLE="S">(SHAPE="SOL" ALIGN="C" STYLE="S">fBsfBd)(SHAPE="SOL" ALIGN="C" STYLE="S">fDsfDd) of 1% accuracy. [Copyright &y& Elsevier]

During the past year the MILL Collaboration has continued its study of heavy-light meson decay constants with three dynamical quarks. Calculations have been extended to a second lattice spacing of about 0.09 fm. At this lattice spacing, there are results in the quenched approximation and for three sets of dynamical quark mass: ml = ms; ml = 0.4ms and ml = 0.2ms, where ml is the light mass for the u and d quarks and ms is the strange quark mass. At the coarser lattice spacing, for which results were presented at Lattice 2001, statistics have been increased for two sets of quark masses and three additional sets of quark masses have been studied, giving a total of eight combinations used to interpolate between the quenched and chiral limits. When these calculations are completed, we can study the decay constants taking into account both chiral and continuum extrapolations. [Copyright &y& Elsevier]

We study the chiral behavior of the ratio of heavy-light decay constants on unquenched lattices with two flavor dynamical quarks using the plaquette gauge action and the nonperturbatively O(a)-improved Wilson fermion action at β = 5.2. The heavy quarks are described by the clover action and the NRQCD action. We find that the sea quark mass dependence of the decay constants largely cancels in the double ratio R1 = SHAPE="BUILT" ALIGN="C" STYLE="S">fBsfBd/SHAPE="BUILT" ALIGN="C" STYLE="S">fDsfDd and the systematic error in the chiral limit can be drastically reduced. Our preliminary result with heavy clover is R1 = 1.018 ± 0.006 ± 0.010, where the first and the second errors are the statistical and the systematics errors. [Copyright &y& Elsevier]

Physical observables which involve fermion loops, such as the chiral condensate, 〈ψψ〉, or matrix elements of the four-fermi operators which_ enter weak decays, require accurate off shell fermion behaviour. We investigate such off-shell contributions to 〈ψψ〉 for domain wall fermions (DWF). After removing the unphysical, short-distance contributions to 〈ψψ〉 by Pauli-Villars subtraction, we compare the mass dependence of the resulting physical quantity, evaluated with both the Wilson and DBW2 gauge actions, since these two actions are known to give quite different 5-dimensional DWF behaviour. We also examine the dependence of the amplitudes entering 〈ψψ〉 on the fifth dimension s, to gain insight into potentially different s-dependence for low- and high-energy modes. Finally, we summarise the present RBC results for conventionally normalised 〈ψψ〉 for the various actions studied. [Copyright &y& Elsevier]

We report on the nucleon decay matrix elements with domain-wall fermions in quenched approximation. Results from direct and indirect method are compared with a focus on the process of a proton decaying to a pion and a lepton. We discuss the renormalization necessary for the matching to the continuum theory. Preliminary results for the renormalized chiral lagrangian parameters are presented. [Copyright &y& Elsevier]