J. S. Miller

Search for inclusive b -> sl(+)l(-)

We have searched for the effective FCNC decays b->s l+l- using an inclusive method. We set upper limits on the branching ratios B(b->s e+e-)<5.7 10^{-5}, B(b->s mu+mu-)<5.8 10^{-5}, and B(b->s e+-mu-+)<2.2 10^{-5} (at 90 %\ C.L.). Combining the di-electron and di-muon decay modes we find: B(b->s l+l-)<4.2 10^{-5} (at 90 % C.L.).We have searched for the effective flavor changing neutral-current decays b{r_arrow}sl{sup +}l{sup {minus}} using an inclusive method. We set upper limits on the branching ratios B(b{r_arrow}se{sup +}e{sup {minus}}){lt} 5.7{times}10{sup {minus}5} , B(b{r_arrow}s{mu}{sup +}{mu}{sup {minus}} ){lt}5.8{times}10{sup {minus}5} , and B(b{r_arrow}se{sup {plus_minus}}{mu}{sup {minus_plus} }){lt}2.2{times}10{sup {minus}5} [at 90{percent} confidence level (C.L.)]. Combing the dielectron and dimuon decay modes we find B(b{r_arrow}sl{sup +}l{sup {minus}}){lt} 4.2{times}10{sup {minus}5} (at 90{percent} C.L.). {copyright} {ital 1998} {ital The American Physical Society}

Studies of radiation damage to CAMEX64 preamplifiers exposed to γ-rays at the Cornell high energy synchrotron source

Abstract CAMEX64 preamplifiers, developed at the MPI-Munich for use in the readout of silicon strip detectors, have been exposed to well-measured doses of monochromatic γ-rays from the Cornell high energy synchrotron source (CHESS) and measurements of the resulting radiation damage have been made. Silicon strip detectors with their associated CAMEXes will be installed close to the interaction region in the CLEO-II experiment at Cornell University, where they will be exposed to both charged particle and photon fluences. Powered and unpowered CAMEXes were irradiated and after each exposure measurements of pedestals, gains, coherent and incoherent noise were made, until the devices could no longer be read out. Results are quoted for noise and gain degradation as a function of dose.

Study of the B0 semileptonic decay spectrum at the Y(4S) resonance

We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral Bs through a partial reconstruction of B{sup 0} {yields} D*{sup -}{ell}{sup +}{nu}. This spectrum, measured with 2.38 fb{sup -1} of data collected at the {Upsilon}(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all {Upsilon}(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B{sup 0} and B{sup +} semileptonic branching fractions, b{sub 0} and b{sub +}, their ratio, and the production ratio f{sub +-}/f{sub 00} of B{sup +} and B{sup 0} pairs at the {Upsilon}(4S). We report b{sub +}/b{sub 0} = 0.950{sub -0.080}{sup +0.117} {+-} 0.091, b{sub 0} = (10.78 {+-} 0.60 {+-} 0.69)%, and b{sub +} = (10.25 {+-} 0.57 {+-} 0.65)%. b{sub +}/b{sub 0} is equivalent to the ratio of charged to neutral B lifetimes, {tau}{sub +}/{tau}{sub 0}.

Studies of double-sided, double metal silicon strip detectors

Abstract We have studied double-sided, double-metal silicon microstrip detectors for the CLEO-II vertex detector. The double-layer structure permits the transverse strips to be connected via longitudinal readout traces to preamplifiers located at the end of the detectors. The detectors are manufactured by Hamamatsu Photonics. They are full size AC coupled detectors with polysilicon bias resistors on the n-side and punchthrough biasing on the p-side. We present measurements of detector static properties, including the extra capacitance due to the double layer structure, as well as measurements of signal and noise.

Studies of double-sided, double-metal silicon microstrip detectors

Double-sided, double-layer silicon microstrip detectors for the CLEO-II vertex detector have been studied. The double-layer structure permits the transverse strips to be connected via longitudinal readout traces to preamplifiers located at the end of the detectors. The detectors are full-size AC coupled detectors with polysilicon bias resistors on the n-side and punch-through biasing on the p-side. The authors present measurements of detector static properties, including the extra capacitance due to the double-layer structure, as well as measurements of signal and noise.<<ETX>>

Studies of radiation damage to CAMEX64 preamplifiers exposed to gamma -rays at the Cornell High Energy Synchrotron Source

CAMEX64 preamplifiers, developed for use in the readout of silicon strip detectors, have been exposed to well-measured doses of monochromatic gamma -rays from the Cornell High Energy Synchrotron Source (CHESS), and measurements of the resulting radiation damage have been made. Silicon strip detectors with their associated CAMEXes will be installed close to the interaction region in the CLEO experiment at Cornell University, where they will be exposed to both charged particle and photon fluences. Powered and unpowered CAMEXes were irradiated and after each exposure measurements of pedestals, gains, and coherent and incoherent noise were made until the devices could no longer be read out. Results are presented for noise and gain degradation as a function of dose. Using well-controlled and calibrated 20 keV synchrotron radiation, failure begins at 20 krad in powered CAMEXes and between 60 and 120 krad in unpowered CAMEXes. These failure levels are considerably larger than the projected radiation dose.<<ETX>>