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Overview and Status Update of the Fermilab HINS Linac R&D Program

Description: The Fermilab High Intensity Neutrino Source (HINS) Linac R&D program is continuing efforts to construct a first-of-a-kind superconducting H{sup -} linac. The goal of the HINS linac is to demonstrate, for the first time, acceleration of high intensity beam with superconducting spoke cavities, control of beam halo growth by use of solenoidal focusing optics throughout, and operation of many cavities from a single high-power RF source for acceleration of non-relativistic particles. The HINS effort is relevant to any future high brightness, high intensity linac and, in particular, to the linac proposed as part of Fermilab Project X to serve the next generation of neutrino physics and future muon storage ring/collider experiments. This paper updates the technical status of the various components being developed, built, and commissioned as a part of HINS and presents the outlook for the HINS program.
Date: May 1, 2009
Creator: Webber, R. C. & Apollinari, G.
Partner: UNT Libraries Government Documents Department

Study of the heavy flavor content of jets produced in W events at the Tevatron collider

Description: We present a detailed study of the heavy flavor content in the W + jet data sample collected with the CDF detector during the 1992-1995 collider run at Fermilab. Rates of heavy flavor jets, identified via the observation of secondary vertices or semileptonic decays of b and c quarks, are in good agreement with a standard model simulation including production of the top quark. An exception is the number of events in which a single jet has both a secondary vertex and a semileptonic decay tag. In the W + 2,3 jet data, we expect 4.4 {+-} 0.6 and we find 13 such events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.
Date: August 1, 2002
Creator: Apollinari, G.
Partner: UNT Libraries Government Documents Department

Fabrication and test of the first normal conducting crossbar H-type accelerating cavity at Fermilab for HINS

Description: The proposed High Intensity Neutrino Source (HINS) at Fermilab is based on an 8 GeV linear proton accelerator that consists of a normal-conducting (warm) and a superconducting section. The warm section is composed of an ion source, a radio frequency quadrupole, a medium energy beam transport (MEBT) and 16 warm Crossbar H-type (CH) cavities that accelerate the beam from 2.5 MeV to 10 MeV (from {beta}=0.0744 to {beta}=0.1422). These warm cavities are separated by superconducting solenoids enclosed in individual cryostats. Beyond 10 MeV, the design uses superconducting spoke resonators to accelerate the beam up to 8 GeV. In this paper, we illustrate the completion of the first warm CH cavity ({beta}=0.0744) explaining in detail the mechanical engineering aspects related to the machining and brazing processes. The radio-frequency (RF) measurements and tuning performed at Fermilab on the resonator and comparisons with simulations are also discussed.
Date: June 1, 2007
Creator: Ristori, L.; Apollinari, G.; Gonin, I.; Khabiboulline, T.; Romanov, G. & /Fermilab
Partner: UNT Libraries Government Documents Department

Heavy flavor physics at the Tevatron

Description: We report on the status of top and b quark physics at the Fermilab Teva-tron collider. In particular, we summarize the knowledge obtained by CDF and D 6 O on the top quark mass and production cross-section. We also present some new interesting results obtained by CDF with the discovery of the Bc meson and a first low statistic measurement of sin(2{beta}) at an hadronic col-lider.
Date: November 1, 1998
Creator: Apollinari, G.
Partner: UNT Libraries Government Documents Department

Design of 325 MHz single and triple spoke resonators at FNAL

Description: The proposed 8-GeV driver at FNAL is based on approximately 400 independently phased SC resonators. In this paper the design of 325 MHz Spoke Resonators, two single spoke resonators ({beta}=0.22 and {beta}=0.4) and a triple spoke resonator ({beta}=0.62), for the High Intensity Neutrino Source (HINS) front end is presented. We describe the optimization of the spoke resonators geometry, the goal being to minimize the E{sub peak}/E{sub acc} and B{sub peak}/E{sub acc} ratios. We report on the coupled ANSYS-MWS analysis on the resonators mechanical properties and power coupler RF design. The current status of mechanical design, slow tuning mechanism and cryostat are also presented.
Date: August 1, 2006
Creator: Lanfranco, G.; Apollinari, G.; Gonin, I.; Khabiboulline, T.; McConologue, F.; Romanov, G. et al.
Partner: UNT Libraries Government Documents Department

Phenomenological study of the atypical heavy flavor production observed at the Fermilab Tevatron

Description: The authors address known discrepancies between the heavy flavor properties of jets produced at the Tevatron collider and the prediction of conventional-QCD simulations. In this study, they entertain the possibility that these effects are real and due to new physics. They show that all anomalies can be simultaneously fitted by postulating the additional pair production of light bottom squarks with a 100% semileptonic branching fraction.
Date: November 1, 2005
Creator: Apollinari, G.; Barone, M.; Fiori, I.; Giromini, P.; Happacher, F.; Miscetti, S. et al.
Partner: UNT Libraries Government Documents Department

Fermilab HINS Proton Ion Source Beam Measurements

Description: The proton ion source for the High Intensity Neutrino Source (HINS) Linac front-end at Fermilab has been successfully commissioned. It produces a 50 keV, 3 msec beam pulse with a peak current greater than 20mA at 2.5Hz. The beam is transported to the radio-frequency quadrupole (RFQ) by a low energy beam transport (LEBT) that consists of two focusing solenoids, four steering dipole magnets and a beam current transformer. To understand beam transmission through the RFQ, it is important to characterize the 50 keV beam before connecting the LEBT to the RFQ. A wire scanner and a Faraday cup are temporarily installed at the exit of the LEBT to study the beam parameters. Beam profile measurements are made for different LEBT settings and results are compared to those from computer simulations. In lieu of direct emittance measurements, solenoid variation method based on profile measurements is used to reconstruct the beam emittance.
Date: May 1, 2009
Creator: Tam, W.M.; Apollinari, G.; Chaurize, S.; Hays, S.; Romanov, G.; Scarpine, V. et al.
Partner: UNT Libraries Government Documents Department

Development of 325 MHz single spoke resonators at Fermilab

Description: The High Intensity Neutrino Source (HINS) project represents the current effort at Fermilab to produce an 8-GeV proton linac based on 400 independently phased superconducting cavities. Eighteen ?=0.21 single spoke resonators, operating at 325 MHz, comprise the first stage of the linac cold section. In this paper we present the current status of the production and testing of the first two prototype cavities. This includes descriptions of the fabrication, frequency tuning, chemical polishing, high pressure rinse, and high-gradient cold tests.
Date: August 1, 2008
Creator: Apollinari, G.; Gonin, I.V.; Khabiboulline, T.N.; Lanfranco, G.; Mukherjee, A.; Ozelis, J. et al.
Partner: UNT Libraries Government Documents Department

Study of sequential semileptonic decays of b hadrons produced at the Tevatron

Description: The authors present a study of rates and kinematical properties of lepton pairs contained in central jets with transverse energy E{sub T} {ge} 15 GeV that re produced at the Fermilab Tevatron collider. They compare the data to a QCD prediction based on the HERWIG and QQ Monte Carlo generator programs. They find that the data are poorly described by the simulation, in which sequential semileptonic decays of single b quarks (b {yields} l c X with c {yields} l s X) are the major source of such lepton pairs.
Date: July 1, 2005
Creator: Apollinari, G.; Fiori, I.; Giromini, P.; Happacher, F.; Miscetti, S.; Parri, A. et al.
Partner: UNT Libraries Government Documents Department

Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

Description: We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum p{sub T} > 0.5 GeV/c, pseudorapidity |{eta}| < 1) produced in association with large transverse momentum jets ({approx}2.2 fb{sup -1}) or with Drell-Yan lepton-pairs ({approx}2.7 fb{sup -1}) in the Z-boson mass region (70 < M(pair) < 110 GeV/c{sup 2}) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-p{sub T} jet production) in each event to define three regions of {eta}-{phi} space; toward, away, and transverse, where {phi} is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-p{sub T} jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.
Date: March 1, 2010
Creator: ,; Aaltonen, T.; Adelman, J.; Gonzalez, B.Alvarez; Amerio, S.; Amidei, D. et al.
Partner: UNT Libraries Government Documents Department

Design and Fabrication of a Single-Aperture 11T Nb3Sn Dipole Model for LHC Upgrades

Description: The planned upgrade of the LHC collimation system includes additional collimators to be installed in the dispersion suppressor areas of points 2, 3 and 7. To provide the necessary longitudinal space for the collimators, a replacement of 8.33 T Nb-Ti LHC main dipoles with 11 T dipoles based on Nb{sub 3}Sn superconductor compatible with the LHC lattice and main systems is being considered. To demonstrate this possibility FNAL and CERN have started a joint program to develop a 2 m long single-aperture dipole magnet with the nominal field of 11 T at {approx}11.85 kA current and 60 mm bore. This paper describes the demonstrator magnet magnetic and mechanical designs and analysis, coil fabrication procedure. The Nb{sub 3}Sn strand and cable parameters and test results are also reported.
Date: November 28, 2011
Creator: Andreev, N.; Apollinari, G.; Barzi, E.; Bossert, R.; Nobrega, F.; Novitski, I. et al.
Partner: UNT Libraries Government Documents Department

Search for anomalous production of multiple leptons in association with $W$ and $Z$ bosons at CDF

Description: This paper presents a search for anomalous production of multiple low-energy leptons in association with a W or Z boson using events collected at the CDF experiment corresponding to 5.1 fb{sup -1} of integrated luminosity. This search is sensitive to a wide range of topologies with low-momentum leptons, including those with the leptons near one another. The observed rates of production of additional electrons and muons are compared with the standard model predictions. No indications of phenomena beyond the standard model are found. A 95% confidence level limit is presented on the production cross section for a benchmark model of supersymmetric hidden-valley Higgs production. Particle identification efficiencies are also provided to enable the calculation of limits on additional models.
Date: February 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

Diffractive Dijet Production in $\bar{p}p$ Collisions at $\sqrt{s}=1.96$ TeV

Description: We report on a study of diffractive dijet production in {bar p}p collisions at {radical}s = 1.96 TeV using the CDF II detector at the Fermilab Tevatron {bar p}p collider. A data sample from 310 pb{sup -1} of integrated luminosity collected by triggering on a high transverse energy jet, E{sub T}{sup jet}, in coincidence with a recoil antiproton detected in a Roman pot spectrometer is used to measure the ratio of single-diffractive to inclusive-dijet event rates as a function of x{sup {bar p}} of the interacting parton in the antiproton, the Bjorken-x, x{sub Bj}{sup {bar p}}, and a Q{sup 2} {approx} (E{sub T}{sup jet}){sup 2} in the ranges 10{sup -3} < x{sub Bj}{sup {bar p}} < 10{sup -1} and 10{sup 2} < Q{sup 2} < 10{sup 4} GeV{sup 2}, respectively. Results are presented for the region of {bar p}-momentum-loss fraction 0.03 < {zeta}{sub {bar p}} < 0.09 and a four-momentum transfer squared t{sub {bar p}} > -4 GeV{sup 2}. The t{sub {bar p}} dependence is measured as a function of Q{sup 2} and x{sub Bj}{sup {bar p}} and compared with that of inclusive single diffraction dissociation. We find weak x{sub Bj}{sup bar p}} and Q{sup 2} dependencies in the ratio of single diffractive to inclusive event rates, and no significant Q{sup 2} dependence in the diffractive t{sub {bar p}} distributions.
Date: June 1, 2012
Creator: Aaltonen, T.; Albrow, M.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Partner: UNT Libraries Government Documents Department

Development of Nb3Sn 11 T single aperture demonstrator dipole for LHC upgrades

Description: The LHC collimation upgrade foresees additional collimators installed in dispersion suppressor regions. To obtain the necessary space for the collimators, a solution based on the substitution of LHC main dipoles for stronger dipoles is being considered. CERN and FNAL have started a joint program to demonstrate the feasibility of Nb{sub 3}Sn technology for this purpose. The goal of the first phase is the design and construction of a 2-m long single-aperture demonstrator magnet with a nominal field of 11 T at 11.85 kA with 20% margin. This paper describes the magnetic and mechanical design of the demonstrator magnet and summarizes its design parameters.
Date: March 1, 2011
Creator: Zlobin, A.V.; Apollinari, G.; Andreev, N.; Barzi, E.; Kashikhin, V.V.; Nobrega, f. et al.
Partner: UNT Libraries Government Documents Department

Design, fabrication and testing of single spoke resonators at Fermilab

Description: The Fermilab High Intensity Neutrino Source (HINS) linac R&D program is building a pulsed 30 MeV superconducting H- linac. The linac incorporates superconducting solenoids, high power RF vector modulators and superconducting spoke-type accelerating cavities starting at 10 MeV. This will be the first application and demonstration of any of these technologies in a low-energy, high-intensity proton/H- linac. The HINS effort is relevant to a high intensity, superconducting H- linac that might serve the next generation of neutrino physics and muon storage ring/collider experiments. In this paper we present the RF design, the mechanical design, the fabrication, the chemistry and testing of the first two SSR1 (Single Spoke Resonator type-1) prototype cavities that were built. These cavities operate at 325 MHz with {beta} = 0.21. The design and testing of the input coupler and the tuning mechanism are also discussed.
Date: September 1, 2009
Creator: Ristori, L.; Apollinari, G.; Borissov, E.; Gonin, I.V.; Khabiboulline, T.N.; Mukherjee, A. et al.
Partner: UNT Libraries Government Documents Department

Search for Standard Model Higgs Boson Production in Association with a $W$ Boson Using a Matrix Element Technique at CDF in $p\bar{p}$ Collisions at $\sqrt{s} = 1.96$ TeV

Description: This paper presents a search for standard model Higgs boson production in association with a W boson using events recorded by the CDF experiment in a dataset corresponding to an integrated luminosity of 5.6 fb{sup -1}. The search is performed using a matrix element technique in which the signal and background hypotheses are used to create a powerful discriminator. The discriminant output distributions for signal and background are fit to the observed events using a binned likelihood approach to search for the Higgs boson signal. We find no evidence for a Higgs boson, and 95% confidence level (C.L.) upper limits are set on {sigma}(p{bar p} {yields} WH) x {Beta}(H {yields} b{bar b}). The observed limits range from 3.5 to 37.6 relative to the standard model expectation for Higgs boson masses between m{sub H} = 100 GeV/c{sup 2} and m{sub H} = 150 GeV/c{sup 2}. The 95% C.L. expected limit is estimated from the median of an ensemble of simulated experiments and varies between 2.9 and 32.7 relative to the production rate predicted by the standard model over the Higgs boson mass range studied.
Date: December 1, 2011
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

$W$ boson polarization measurement in the $t\bar{t}$ dilepton channel using the CDF II Detector

Description: We present a measurement of W boson polarization in top-quark decays in t{bar t} events with decays to dilepton final states using 5.1 fb{sup -1} integrated luminosity in p{bar p} collisions collected by the CDF II detector at the Tevatron. A simultaneous measurement of the fractions of longitudinal (f{sub 0}) and right-handed (f{sub +}) W bosons yields the results f{sub 0} = 0.71{sub -0.17}{sup +0.18}(stat) {+-} 0.06(syst) and f{sub +} = -0.07 {+-} 0.09(stat) {+-} 0.03(syst). Combining this measurement with our previous result based on single lepton final states, we obtain f{sub 0} = 0.84 {+-} 0.09(stat) {+-} 0.05(syst) and f{sub +} = -0.16 {+-} 0.05(stat) {+-} 0.04(syst). The results are consistent with standard model expectation.
Date: May 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

A Search for dark matter in events with one jet and missing transverse energy in $p\bar{p}$ collisions at $\sqrt{s} = 1.96$ TeV

Description: We present the results of a search for dark matter production in the monojet signature. We analyze a sample of Tevatron pp collisions at {radical}s = 1.96 TeV corresponding to an integrated luminosity of 6.7 fb{sup -1} recorded by the CDF II detector. In events with large missing transverse energy and one energetic jet, we find good agreement between the standard model prediction and the observed data. We set 90% confidence level upper limits on the dark matter production rate. The limits are translated into bounds on nucleon-dark matter scattering rates which are competitive with current direct detection bounds on spin-independent interaction below a dark matter candidate mass of 5 GeV/c{sup 2}, and on spin-dependent interactions up to masses of 200 GeV/c{sup 2}.
Date: March 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

Measurement of $B_s^0 \to D_s^{(*)+} D_s^{(*)-}$ Branching Ratios

Description: The decays B{sub s}{sup 0} {yields} D{sub s}{sup (*)+}D{sub s}{sup (*)-}s are reconstructed in a data sample corresponding to an integrated luminosity of 6.8 fb{sup -1} collected by the CDF II detector at the Tevatron p{bar p} collider. All decay modes are observed with a significance of more than 10 {sigma}, and we measure the B{sub s}{sup 0} production rate times B{sub s}{sup 0} {yields} D{sub s}{sup (*)+} D{sub s}{sup (*)-} branching ratios relative to the normalization mode B{sup 0} {yields} D{sub s}{sup +}d{sup -} to be 0.183 {+-} 0.021 {+-} 0.017 for B{sub s}{sup 0} {yields} D{sub s}{sup +}D{sub s}{sup -}, 0.424 {+-} 0.046 {+-} 0.035 for B{sub s}{sup 0} {yields} D{sub s}{sup {+-}} D{sub s}{sup {-+}}, 0.654 {+-} 0.072 {+-} 0.065 for B{sub s}{sup 0} {yields} D{sub s}{sup *+} D{sub s}{sup *-}, and 1.261 {+-} 0.095 {+-} 0.112 for the inclusive decay B{sub s}{sup 0} {yields} D{sub s}{sup (*)+}D{sub s}{sup (*)-}, where the uncertainties are statistical and systematic. These results are the most precise single measurements to date and provide important constraints for indirect searches for non-standard model physics in B{sub s}{sup 0} mixing.
Date: April 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the Top Quark Mass in the All-Hadronic Mode at CDF

Description: A measurement of the top quark mass (M{sub top}) in the all-hadronic decay channel is presented. It uses 5.8 fb{sup -1} of p{bar p} data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines M{sub top} and the jet energy scale (JES) calibration. The fit yields a value of M{sub top} = 172.5 {+-} 1.4 (stat) {+-} 1.0 (JES) {+-} 1.1 (syst) GeV/c{sup 2}.
Date: December 1, 2011
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

Measurement of $ZZ$ production in leptonic final states at $\surd{s}$ of 1.96 TeV at CDF

Description: In this paper we present a precise measurement of the total ZZ production cross section in p{bar p} collisions at {radical}s = 1.96 TeV, using data collected with the CDF II detector corresponding to an integrated luminosity of approximately 6 fb{sup -1}. The result is obtained by combining separate measurements in the four-charged ({ell}{ell}{ell}{prime}{ell}{prime}), and two-charged-lepton and two-neutral-lepton ({ell}{ell}{nu}{nu}) decay modes of the Z. The combined measured cross section for p{bar p} {yields} ZZ is 1.64{sub -0.38}{sup +0.44} pb. This is the most precise measurement of the ZZ production cross section in 1.96 TeV p{bar p} collisions to date.
Date: December 1, 2011
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the $WZ$ Cross Section and Triple Gauge Couplings in $p \bar p$ Collisions at $\sqrt{s} = 1.96$ TeV

Description: This Letter describes the current most precise measurement of the WZ production cross section as well as limits on anomalous WWZ couplings at a center-of-mass energy of 1.96 TeV in proton-antiproton collisions. The WZ candidates are reconstructed from decays containing three charged leptons and missing energy from a neutrino, where the charged leptons are either electrons or muons. Using data collected by the CDF II detector (7.1 fb{sup -1} of integrated luminosity), 64 candidate events are observed with the expected background contributing 8 {+-} 1 events. The measured total cross section {sigma}(p{bar p} {yields} WZ) = 3.93{sub -0.53}{sup +0.60}(stat){sub -0.46}{sup +0.59}(syst) pb is in good agreement with the standard model prediction of 3.50 {+-} 0.21. The same sample is used to set limits on anomalous WWZ couplings.
Date: February 1, 2012
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Partner: UNT Libraries Government Documents Department