Significant progress toward measuring the CKM angle alpha has been made by the B-factories over the past decade. This work has culminated in a constraint on alpha with a precision of less than 4 degrees.
B-meson decays involving b->u transitions are sensitive to the Unitarity Triangle angle alpha (or phi_2). The B-factories at SLAC and KEK have made significant progress toward the measurement of alpha in recent years. This paper summarizes the results of the B-factories' constraints on alpha.
The measurements of the angle alpha (phi2) of the unitarity triangle at the B factories are reviewed. The value of alpha determined by combining the results obtained in the B to pi pi, B to rho pi, and B to rho rho modes by both the BABAR and Belle experiments is (87.5 +6.2 -5.3) degrees.
The current results on B to pipi decays and SU2 constraints on the Unitarity Triangle angle alpha or phi_2 from the B-factories are summarised. Based on these measurements, predictions of the isospin analysis constraints at the end of the lifetime of both B-factories are given.
The CKM angle $γ/ϕ_{3}$ had been measured by two B-factories, the PEPII collider for the BaBar experiment and the KEKB collider for the Belle experiments. The present paper reports recent progress in $γ/ϕ_{3}$.
Recent results on inclusive and exclusive semileptonic B decays from B-factories are presented. The impact of these measurements on the determination of the CKM matrix elements |Vub| and |Vcb| is discussed.
The determination of the Vub element of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix plays a central role in testing the Standard Model (SM) interpretation of CP violation. Measurements at B-Factories are contributing with results that rely on different theoretical assumptions. Recent inclusive and exclusive results from CLEO, BaBar and BELLE are reviewed.
Recent measurements of time dependent CP asymmetries at the B factories have led to substantial progress in our understanding of CP violation. In this article, I review some of these experimental results and discuss their implications in the Standard Model and their sensitivity to New Physics.
On behalf of the Babar and Belle collaborations, we report on the measurement of the angle gamma and on the sum of angles 2 beta+gamma of the Unitarity Triangle.
We report measurements of time-dependent CP asymmetries related to the CKM angle $β/ϕ_1$, using decays of neutral B mesons to charmonium, open charm and in $b\to s$ loop processes. A preliminary measurement of time-dependent CP asymmetries in $B^0\to ρ^0(770) K^0_S$ decays from the BaBar experiment is given here.
In this proceeding, we report the recent measurements of the CKM angle ϕ_1(β) using large data samples collected by the Belle and BaBar experiments. The experiments have collected more than 1 billion B anti-B pairs of data sample at the Υ(4S) resonance using the facilities of the asymmetric-energy e+e- colliders KEKB and PEP-II.
We review recent measurements of leptonic $D_s$-meson decays performed by Belle and BaBar collaborations. Described measurements enable experimental extraction of the $D_s$-meson decay constant which can be compared with lattice QCD calculations.
Recent results and future prospects for Y(5S) running at B-factories are discussed. The first Belle measurements with 23.6 fb-1 of data taken at the Y(5S) energy are reported. Eligibility of potential measurements expected with 100 fb-1 and 1000 fb-1 of data at the Y(5S) is estimated.
Today the B-factories BaBar and Belle have accumulated largest samples of tau-tau events and are competing to be called tau-factories. Among the problems to be tested and measurements to be done by BaBar and Belle are check of CP and CPT invariance in tau decays, measurement of strange and non-strange spectral functions, extraction of mass of strange quark and |V_us|, searches for lepton flavor violation processes. In this paper, the latest results in tau physics by these two experiments and measurements to be done within next few years are reviewed.
In this talk we present the perspectives about measurements of CP and CPT violating quantities at future Super Flavour Factories. In particular we will focus on the expected sensitivities reachable after 5 years of data taking with the SuperB detector: this dataset will allow to perform measurements on B meson, D meson and tau lepton systems with greatly enhanced precision over the current results.
I report here recent measurements of observables from the inclusive decays $B\to X_sγ$ and $B\to X_s\ell^+\ell^-$. Included are measurements of the branching fractions and CP asymmetries for both channels, as well as the forward-backward lepton asymmetry in inclusive $B\to X_s\ell^+\ell^-$ decays, which is the first measurement of this quantity.
Recent measurements of hadronic branching fractions of D and Ds mesons, performed by the BaBar and Belle experiments at the asymmetric e+e- B factories colliders PEP II and KEKB, are reviewed.
We review recent progress at the two $e^+ e^-$ B factories. The first measurement of CP violation and the prospects for measuring all the angles of the unitarity triangle are discussed.
Current experiments at the B factories, designed to perform precision measurements of matter-antimatter asymmetry in the B meson system, have a much broader physics reach especially in the sector of quarkonium spectroscopy. Here we present a minireview on the new charmonium-like states observed at the B factories including the X(3872) and Y(4260).
The efforts to improve on the precision of the measurement and theoretical prediction of the anomalous magnetic moment of the muon a_mu have turned into a test of our understanding of the hadronic contribution to vacuum polarisation. I describe how recent measurements of hadron production in e+e- interactions with initial-state radiation provide precision measurements of the hadron cross section, and have improved on the contribution to the prediction of the value of a_mu that dominates the global uncertainty.
An overview is given on recent progress in the study of quarkonium spectroscopy at the B-factories. In particular, an updated status report is presented of the long list of "charmonium-like" resonances newly discovered, whose assignment as true charmonium states is in most cases at least controversial. Also, new measurements on the decay properties of bottomonium states above open-B production thresholds are shown.
We present a review of the measurements of the CKM angle beta (phi_1) by the BaBar and Belle experiments at the asymmetric-energy e+e- B Factories PEP-II and KEKB. The angle beta (phi_1) is measured by time-dependent CP analyses of neutral B meson decays in a Upsilon(4S)->BBbar system, where one B meson is fully reconstructed in a final state that can be accessed to by both B0 and B0bar, usually a CP eigenstate. This angle has been measured at a high precision through B0-> (ccbar)K0 channels. We also review another tree-dominated decay B0-> D(*)0 h0 (h0 = pi0, eta^{'}, omega); tree decays with…
Based on background measurements at PEP II the impact of machine-related backgrounds on individual components of multipurpose detectors is examined, that operate in an asymmetric B factory at luminosities up to 10^{36} cm^{-2} s^{-1}. Extrapolations of the BABAR experience suggests two feasible detector designs.
Recent measurements at the B factories of CKM matrix elements affecting CP-violation are reviewed. The emphasis is on the unitarity triangle. Some aspects of the charm and tau sectors are mentioned.
Recent measurements of branching fractions, form factors and decay constants of leptonic and semileptonic decays of D_(s)-mesons acquired at experiments running at the Upsilon(4S) resonance energy are reviewed.
The luminosity determination of electron-positron colliders operating in the region of low-lying hadronic resonances (E_cm ~ 1-10 GeV), such as BEPC/BES, DAPHNE, KEKB, PEP-II and VEPP-2M, requires the precision calculation of the Bhabha process at large scattering angles. In order to achieve a theoretical accuracy at a few 0.1% level, the inclusion of radiative corrections is mandatory. The phenomenologically relevant effect of QED corrections is taken into account in the framework of the Parton Shower (PS) method, which is employed both for cross section calculation and event generation. To t…
BABAR and Belle measurements of branching fractions, rate asymmetries and angular observables in the decay modes B \to K(*)l+l- are reviewed and new results from CDF on B \to K(*)μ+μ- branching fractions and angular observables are discussed. A first search for B+ \to K+τ+τ- is presented.
We report measurements of hadronic final states produced in $e^+e^-$ annihilations from the BaBar and Belle experiments. In particular, we present cross sections measured in several different processes, including two-photon physics, Initial-State Radiation, and exclusive hadron productions at center-of-mass energies near 10.58 GeV. Results are compared with theoretical predictions.
We report on recent measurements, from the BaBar and Belle experiments, of B-meson decays to purely hadronic final states that do not contain charm. The studies are based on large samples of BBbar pairs collected at the Upsilon(4S) or B_s(*)B_s(*) pairs collected at the Upsilon(5S) by the BaBar and Belle detectors at the asymmetric energy e+e- colliders at SLAC and KEK-B, respectively. This paper includes the following results: measurements of branching fractions and charge asymmetries of B meson decays to eta' rho, eta' f0, and eta' K*, where the K* stands for a vector, tensor, or scalar stra…
We present an overview of a study on precise mass reconstruction and identification of charged hadrons ($π^{\pm}$, $K^{\pm}$, $p$) using time-of-flight measurements in the electromagnetic calorimeter of a typical Higgs factory detector. Time-of-flight measurements can take advantage of fast timing Si sensors with a time resolution in the order of 10 ps. A precise time-of-flight measurement might contribute to the kaon mass determination and can improve particle identification in the momentum regions inaccessible for the $dE/dx$ method. In this contribution, we discuss the current status and th…
While the particle physics community is eagerly waiting for a positive sign for the construction of the next energy frontier collider, developments continue to advance the detector capabilities. New methods and algorithms are being implemented in order to exploit the precious collisions at a Future Higgs Factory as well as possible, informing at the same time, which detector aspects are of particular importance or in fact currently limiting. In this work, three new event analysis methods are briefly introduced and put into context of hardware development for a detector at a Future Higgs Factor…
We review the salient features of $B$-meson physics, with particular emphasis on the measurements carried out at the $B$-factories and Tevatron, theoretical progress in understanding these measurements in the context of the standard model, and anticipation at the LHC. Topics discussed specifically are the current status of the Cabibbo-Kobayashi-Maskawa matrix, the CP-violating phases, rare radiative and semileptonic decays, and some selected non-leptonic two-body decays of the $B$ mesons.
The radiative return offers the unique possibility for a measurement of the cross section of electron--positron annihilation into hadrons over a wide range of energies. The large luminosity of present phi- and B-factories easily compensates for the additional factor of alpha due to the emission of a hard photon. Final states with photons at large angles can be easily identified. The rate for events with collinear photons, however, is enhanced by a large logarithm and allows, in particular at lower energies, for a complementary measurement. The Monte Carlo generator PHOKHARA, which includes nex…
Integrated Luminosity with 100 ppm Precision, Methods for $\sqrt{s}$ Precision of 1 ppm, and Beyond Standard Model Sensitivity using Photonic Events, at $\mathrm{e^{+}e^{-}}$ Higgs Factories
We present a review on the measurements of the CKM angle gamma (phi_3) as performed by the BABAR and Belle experiments at the asymmetric-energy e+e- B factories colliders PEP-II and KEKB.
We demonstrate how probes of CP-violating observables in Higgs di-tau decays at prospective future lepton colliders could provide a test of weak scale baryogenesis with significant discovery potential. Measurements at the Circular Electron Positron Collider, for example, could exclude a CP phase larger than $2.9^\circ$ ($5.6^\circ$) at 68% (95%) C.L. assuming the Standard Model value for magnitude of the tau lepton Yukawa coupling. Conversely, this sensitivity would allow for a $5\,σ$ discovery for 82% of the CP phase range $[0,2π)$. The reaches of the Future Circular Collider - ee and Interna…
We report the current status of Delta-md measurements at B-factories. The most recent world average is Delta-md = 0.502+-0.007 1/ps (1.4% accuracy). An estimate of the errors for 500 1/fb data is also given.
B factories measure the CP violation parameter of B^0 Bbar^0 mixing and decay. Hadron colliders measure the dimuon charge asymmetry of an admixture of B hadrons. In this note we discuss a subtle point on how the CP violation parameter of B^0_s Bbar^0_s mixing and decay can be extracted from these measurements.
$b\to sτ^+τ^-$ measurements are highly motivated for addressing lepton-flavor-universality (LFU)-violating puzzles such as $R_{K^{(\ast)}}$ anomalies. The anomalies of $R_{D^{(*)}}$ and $R_{J/ψ}$ further strengthen their necessity and importance, given that the LFU-violating hints from both involve the third-generation leptons directly. $Z$ factories at the future $e^-e^+$ colliders stand at a great position to conduct such measurements because of their relatively high production rates and reconstruction efficiencies for $B$ mesons at the $Z$ pole. To fully explore this potential, we pursue a …
Future asymmetric e+e- --> Upsilon(4S) B factories are being constructed to search for CP violation in B0 decays. It is hoped that a CP asymmetry may be observed in B0-B0bar mixing in analogy with that found in neutral kaons. In this mixing measurement, B0 decays to CP eigenstates, such as the rare decay B0 psi Kshort, may provide information on the CKM angle sin(2beta). I discuss decay additional CP eigenstate branching ratios measured by the CLEO experiment that may be used by future B factories to measure sin(2beta).
Recent determinations of alphas(Mz) from the H1 and ZEUS Collaborations using inclusive-jet cross-section measurements in neutral current deep inelastic scattering at high Q2 are presented. A combined value of alphas(mz)=0.1198 +- 0.0019 (exp.) +- 0.0026 (th.) was obtained from these measurements. The determinations of alphas at various scales clearly show the running of the coupling from HERA jet data alone and in agreement with the prediction of QCD.
The LEP experiments have measured event shapes using data taken at e+e- center-of-mass energies ranging from 91 GeV to 209 GeV. Using the final LEP event shape measurements, a combined value of the strong coupling constant alpha_s(M_Z) has been extracted. Events with photon radiation have been used to extend the measurements to lower center-of-mass energies sqrt(s') to study the running of alpha_s. Alternative alpha_s measurements using four-jet rates have also been performed.
The precision measurements of the strong coupling constant, alphas, and its energy-scale dependence carried out at HERA by the H1 and ZEUS Collaborations are reviewed. An average value of alphas(Mz) = 0.1186 +- 0.0011 (exp.) +- 0.0050 (th.) is obtained from these measurements. The combined HERA determinations of the energy-scale dependence of alphas clearly show the running of alphas from jet data alone and are in agreement with the running of the coupling as predicted by QCD.
Data from e+e- annihilation into hadrons collected by the JADE, the L3 and the OPAL experiment at centre-of-mass energies between 14 GeV and 209 GeV are used to determine the strong coupling alpha_S. Observables in leading order sensitive to alpha_S as well as alpha_S**2 are used. The evolution of alpha_S with respect to the centre-of-mass energy as predicted by QCD is studied and confirmed with high precision. All measurements of alpha_S are consistent with the current world average.
A survey is presented of recent measurements in jet physics, and improved determinations of the QCD coupling constant alpha_s that these have made possible.
We present the latest Next-to-Next-Leading order strong coupling constant, alpha-s, extracted from Gross-Llewellyn-Smith sum rule. The value of alpha-s from this measurement, at the mass of Z boson, is alpha-s^{NNLO}(M_Z**2)=0.114^{+0.009}_{-0.012}. We discuss the previous strange sea quark measurement from the CCFR experiment and the prospects for improvements of the measurement in the NuTeV experiment.
Recent experimental results on CP violation in the B sector from BABAR and BELLE, experiments at asymmetric e+e- B-Factories, are summarized in these proceedings. The constraint on the position of the apex of the unitary triangle, obtained from these measurements allows a test of the CKM interpretation of CP violation in thae Standard Model.
We present recent measurements of the CKM angle alpha using data collected by the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider at the SLAC National Accelerator Laboratory, operating at the Upsilon(4S) resonance. We present constraints on alpha from B->pipi, B->rhorho and B->rhopi decays.
Hadronic event shape distributions are determined from data in e+e- collisions between 183 and 207 GeV. From these the strong coupling alpha_s is extracted in O(alpha_s^2), NLLA and matched O(alpha_s^2)+NLLA theory. Hadronisation corrections evaluated with fragmentation model generators as well as an analytical power ansatz are applied. Comparing these measurements to those obtained at and around M_Z allows a combined measurement of alpha_s from all DELPHI data and a test of the energy dependence of the strong coupling.
A summary is given of the current status of measurements of the strong coupling constant $α_s$ performed at LEP. These include measurements from inclusive observables as well as from event shape variables. Recent results based on power law corrections are discussed.
We present a summary of the measurements of the CKM angle, alpha (phi2), performed by the BaBar and Belle experiments which collect BBbar pairs at the Y(4S) resonance produced in asymmetric e+ e- collisions. We discuss the measurements of the branching fractions and CP asymmetries in the B --> pi pi, rho pi and rho rho final states that lead to constraints on alpha (phi2).
The prospects for the measurement of the strong coupling constant alpha_msbar(M_Z) to a relative uncertainty of 1% are discussed. Particular emphasis is placed on the implications relating to future High Energy Physics facilities.
Determinations of alpha_s are reviewed. Current results are limited to a precision of around 3-20%, largely by theoretical uncertainties. All measurements are consistent with a `world average' value of 0.118 +- 0.005 and there is no evodence of any discrepancy between `low-Q^2' and `high-Q^2' results.
We present recent measurements of the unitarity triangle angle phi2(alpha) using B -> pi pi, B -> rho rho, and B -> rho pi decays. The measurements are based on data samples collected with the Belle and BaBar detectors at the KEKB and PEP-II e+e- colliders, respectively. We also report on a new measurement of a CP-violating asymmetry in B -> a_1+ pi- decay which will allow to constrain further the angle phi2.