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The ZEUS experiment has measured charm production in diffractive DIS and in photoproduction. The data are in agreement with perturbative QCD calculations based on various parameterisations of diffractive parton distribution functions. The results are consistent with QCD factorisation in diffractive DIS and direct photoproduction.
Small-angle detectors at the LHC give access to a broad physics programme within and beyond the Standard Model (SM). We review the capabilities of ALICE, ATLAS, CMS, LHCb, LHCf and TOTEM for forward physics studies in various sectors: soft and hard diffractive processes, exclusive Higgs production, low-x QCD, ultra-high-energy cosmic-rays, and electro-weak measurements.
The Callan-Treiman low-energy theorem offers an opportunity to test electroweak couplings of light quarks to the gauge boson W. To that aim, we introduce a model-independent and accurate dispersive parametrization of the two K_{l3} form factors. We then discuss three applications to the analysis of K_{e3} and K_{mu3} measurements: the prediction of the ratios Gamma(K_{mu3})/Gamma(K_{e3}), the extraction of |f_+(0)V_{us}| and finally the possible measurement of m_u - m_d induced isospin breaking asymmetry.
Updating our previous measurements with new data and analysis modifications, we report preliminary results on the energy-dependent deficit of muon neutrinos from the Fermilab NuMI beam as observed with the MINOS Far Detector located 735 km away in the Soudan Underground Laboratory. From an exposure of 2.50x10^20 protons on target, we observe 563 charged-current nu_mu interaction candidates in the Far Detector, where 738+/-30 events are expected in the absence of neutrino oscillations. We have analyzed these data assuming two-flavor nu_mu to nu_tau oscillations. From a simultaneous fit to the reconstructed nu_mu energy spectra obtained during two running periods we obtain the neutrino squared-mass difference Delta m_{32}^2 = (2.38 +0.20/-0.16) x 10^-3 eV^2/c^4 with errors at 68% confidence level (CL), and mixing angle sin^2(2 theta_23) > 0.84 at 90% CL. The uncertainties and confidence intervals include both statistical and systematic errors. All results and plots presented here are preliminary.
The considerable center-of-mass energy and luminosity provided by the Large Hadron Collider (LHC) will ensure a discovery reach for new particles which extends well into the multi-TeV region. ATLAS and CMS have carried out many studies of the implications of this capability for Beyond the Standard Model physics. In this paper, we summarize some key results of studies involving non-susy models, such as extra-dimensions, little higgs, compositeness, and left-right symmetric models.
We study the decay B0 --> rho0 rho0 in a sample of about 427 million Upsilon(4S) --> BBbar decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find the branching fraction B = (0.84 +/- 0.29 +/- 0.17)*1e-6 and longitudinal polarization fraction of f_L = 0.70 +/- 0.14 +/- 0.05, where the first uncertainty is statistical, and the second is systematic. The evidence for the B0 --> rho0 rho0 signal has 3.6 sigma significance. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S^{00}_L = 0.5 +/- 0.9 +/- 0.2 and C^{00}_L = 0.4 +/- 0.9 +/- 0.2, corresponding to the sine and cosine terms in the time evolution of asymmetry. We study the implication of these results for penguin contributions in B --> rho rho decays and for the CKM unitarity angle alpha.
We report an improved measurement of the B+ -> D+ D0bar and B0 -> D0 D0bar decays based on 656.7 10^6 BBar events collected with the Belle detector at KEKB. We measure the branching fraction and charge asymmetry for the B+ -> D+ D0bar decay: Br(B+ -> D+ D0bar)= (3.85 +- 0.31 +- 0.38) 10^-4 and A_{CP}(B+ -> D+ D0bar)=0.00 +- 0.08 +- 0.02, where the first error is statistical and the second is systematical. We also set the upper limit for the B0 -> D0 D0bar decay: Br(B0 -> D0 D0bar) < 0.42 10^-4 at 90% CL.
We present new parameterizations of vector and axial nucleon form factors. We maintain an excellent descriptions of the form factors at low momentum transfers, where the spatial structure of the nucleon is important, and use the Nachtman scaling variable ξto relate elastic and inelastic form factors and impose quark-hadron duality constraints at high momentum transfers where the quark structure dominates. We use the new vector form factors to re-extract updated values of the axial form factor from neutrino experiments on deuterium. We obtain an updated world average value from neutrino and pion electroproduction experiments of M_A = 1.0144 +- 0.0136 GeV/c2. Our parameterizations are useful in modeling atmospheric neutrino interactions (e.g. for neutrino oscillations experiments)
The LHCb detector has been designed to study CP violation and other rare phenomena in B-meson decays up to a luminosity of $\sim 5.10^{32}\rm cm^{-2}s^{-1}$. This paper will describe what is limiting LHCb to exploit the much higher luminosities available at the LHC, and what are the baseline modifications which will remedy these limitations. The aim of SuperLHCb is to increase the yields in hadronic B-decay channels by about a factor twenty compared to LHCb, while for channels with leptons in the final state a factor ten increase in statistics is envisaged.
In the past 10 years our knowledge of the parameters rho and eta of the Cabibbo-Kobayashi-Maskawa matrix has improved substantially. This article reviews the measurements that contributed to this advance, and discusses their implication in terms of understanding CP violation in the Standard Model and beyond.
Several topics in the Kphysics together with the new facility J-Parc are introduced.
Flavor physics is about particle mass-degeneracy-deviations (DMD) and mixing and especially about hierarchies of those deviations. On the one hand there is no established theory of particle flavor at present; on the other hand there are growing data indications on interesting empirical flavor regularities that are described here by two semi-empirical rules: quadratic DMD-hierarchy and Dirac-Majorana DMD-duality rules. First rule unites neutrino solar-atmospheric hierarchy parameter with charged lepton (CL) and quark mass-ratio hierarchies and simultaneously unites the hierarchies in the mixing matrices of quarks and neutrinos; the second rule predicts quasi-degenerate neutrinos from the fact of CL and quark large mass hierarchy and explains quark-neutrino complementarity mixing relations. The neutrino and quark mixing data seem very different, but it results that small deviations from maximal neutrino mixing are nearly equal to the small deviations from minimal mixing of quarks. Those deviations are quantitatively described by only one new small flavor parameter ~0.0067.
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.
Recent results from CLEO-c, BABAR, and Belle on measurements of absolute branching fractions of D and D_s mesons are reviewed.
We report an observation of the decay B0 -> D*- tau+ nu and a search for the rare decays B -> h(*) nu nubar\ove, where h(*) stands for a light meson. A data sample of 535 million BBbar pairs collected with the Belle detector at the KEKB e+e- collider is used. We find a signal with a significance of 5.2 standard deviations on B0 -> D*- tau+ nu and measure the branching fraction to be 2.02 +0.40/-0.37 (stat.) +- 0.37 (syst.)%. No significant signal is observed for B -> h(*) nu nubar decays and we set upper limits on the branching fractions at 90% confidence level. The limits on B0 -> K*0 nu nubar and B+ -> K+ nu nubar decays are more stringent than the previous constraints, while the first searches for B0 -> K0 nu nubar, pi0 nu nubar, rho0 nu nubar, phi nu nubar and B+ -> K*+ nu nubar, rho+ nu nubar are presented.
We review searches for mixing and CP violation in the D0-D0bar system and discuss the first evidence for mixing recently obtained by the Belle and BABAR collaborations. We also present world average values for the mixing parameters x=Delta m/Gamma and y=Delta Gamma/(2 Gamma) as calculated by the Heavy Flavors Averaging Group.
A review is presented of the current status of experimental searches for physics beyond the standard model in rare $τ$ decays.
Longitudinal spin physics program at RHIC-PHENIX is introduced. Recent results of pi0 cross section and A_LL are presented and discussed.