Future Colliders

Abstract:

We search for b→sμ+μ- transitions in B meson (B+, B0, or Bs0) decays with 924pb-1 of pp̄ collisions at s=1.96TeV collected with the CDF II detector at the Fermilab Tevatron. We find excesses with significances of 4.5, 2.9, and 2.4 standard deviations in the B+→μ+μ-K+, B0→μ+μ-K*(892)0, and Bs0→μ+μ- decay modes, respectively. Using B→J/ψh (h=K+, K*(892)0,) decays as normalization channels, we report branching fractions for the previously observed B+ and B0 decays, B(B+→μ+μ-K+)=(0.59±0.15±0. 04)×10-6, and B(B0→μ+μ-K*(892)0)=(0.81±0. 30±0.10)×10-6, where the first uncertainty is statistical, and the second is systematic. We set an upper limit on the relative branching fraction B(Bs0→μ+μ-)/B(Bs0→J/ψ)<2.6(2.3)×10-3 at the 95(90)% confidence level, which is the most stringent to date. © 2009 The American Physical Society.

Abstract:

Deeply virtual Compton scattering, γ*p→γp has been measured in e+p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb-1. Cross sections are presented as a function of the photon virtuality, Q2, and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q2 > 1.5GeV2 and 40 < W < 170GeV. A subsample of events in which the scattered proton is measured in the leading proton spectrometer, corresponding to an integrated luminosity of 31.3 pb-1, is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex. © SISSA 2009.

Abstract:

In-situ Storage Image Sensor (ISIS) is a new detector concept being developed by the Linear Collider Flavour Identification collaboration for a future vertex detector at the ILC. ISIS1 was the first prototype and was used to test the operational principles. ISIS2 is the second generation of the family, and is made on a submicron CMOS process to reduce the pixel size. Characterisation of the test structures built along with the main part of the sensor array are reported here, including the readout noise, the cell well-capacity and the fringing-field effects. Preliminary results of the test on the main array are also discussed. The results indicate that ISIS is an extremely promising design for the ILC.

Abstract:

Recent ZEUS measurements of inclusive-jet and dijet cross sections in neutral current deep inelastic ep scattering at HERA are presented. The data correspond to more than a two-fold increase in statistics compared to previous studies. The cross sections are measured in the Breit frame, for boson virtualities of Q2 > 125 GeV2, as functions of various kinematic and jet observables. The data are found to be well described by NLO QCD and have the potential to constrain the gluon density in the proton. Two new extractions of the strong coupling, αs, are also presented: the first is determined from the inclusive-jet neutral current DIS measurement presented here, while the second is from a re-analysis of previously published data on inclusive jet photoproduction. Both measurements are of competitive precision and in agreement with the world average.