We present various properties of the production of the X(3872) and ψ(2S) states based on 10.4 fb−1 collected by the D0 experiment in Tevatron pp collisions at √s = 1.96 TeV. For both states, we ...measure the nonprompt fraction fNP of the inclusive production rate due to decays of b-flavored hadrons. We find the fNP values systematically below those obtained at the LHC. The fNP fraction for ψ(2S) increases with transverse momentum, whereas for the X(3872) it is constant within large uncertainties, in agreement with the LHC results. The ratio of prompt to nonprompt ψ(2S) production, (1 − fNP)=fNP, decreases only slightly going from the Tevatron to the LHC, but for the X(3872), this ratio decreases by a factor of about 3. We test the soft-pion signature of the X(3872) modeled as a weakly bound charm-meson pair by studying the production of the X(3872) as a function of the kinetic energy of the X(3872) and the pion in the X(3872)π center-of-mass frame. For a subsample consistent with prompt production, the results are incompatible with a strong enhancement in the production of the X(3872) at the small kinetic energy of the X(3872) and the π in the X(3872)π center-of-mass frame expected for the X þ soft-pion production mechanism. For events consistent with being due to decays of b hadrons, there is no significant evidence for the soft-pion effect, but its presence at the level expected for the binding energy of 0.17 MeV and the momentum scale Λ ¼ M(π) is not ruled out.
We present a combination of measurements of the top quark mass by the D0 experiment in the lepton+jets and dilepton channels. We use all the data collected in Run I (1992–1996) at s=1.8 TeV and Run ...II (2001–2011) at s=1.96 TeV of the Tevatron pp¯ collider, corresponding to integrated luminosities of 0.1 fb−1 and 9.7 fb−1, respectively. The combined result is: mt=174.95±0.40(stat)±0.64(syst) GeV=174.95±0.75 GeV.
SPD Range (Muon) System Abazov, V. M.; Alexeev, G. D.; Golovanov, G. A. ...
Physics of particles and nuclei,
07/2021, Letnik:
52, Številka:
4
Journal Article
Recenzirano
The range system (RS) is one of the essential detectors of the spin physics detector (SPD) which is currently under preparation for the second interaction point of the NICA collider. RS provides ...identification of muons and can also be used as a coarse hadronic calorimeter. The SPD range system design and geometry modeling are presented as well as the main results of RS prototype tests.
The thin-wall tube drift chamber operating in vacuum (prototype) Alexeev, G.D.; Glonti, L.N.; Kekelidze, V.D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Letnik:
718
Journal Article
Recenzirano
The goal of this work was to design drift tubes and a chamber operating in vacuum, and to develop technologies for tubes independent assembly and mounting in the chamber. These design and technology ...were tested on the prototype. The main features of the chamber are the following: the drift tubes are made of flexible mylar film (wall thickness 36μm, diameter 9.80mm, length 2160mm) using ultrasonic welding along the generatrix; the welding device and methods were developed at JINR. Drift tubes with end plugs, anode wires and spacers were completely assembled outside the chamber. “Self-centering” spacers and bushes were used for precise setting of the anode wires and tubes. The assembled tubes were sealed with O-rings in their seats in the chamber which simplified the chamber assembling. Moreover the tube assembly and the chamber manufacture can be performed independently and in parallel; this sufficiently reduces the total time of chamber manufacture and assembling, its cost and allows tubes to be tested outside the chamber. The technology of independent tube assembling is suitable for a chamber of any shape but a round chamber is preferable for operation in vacuum. Single channel amplifier-discriminator boards which are more stable against cross talks were used for testing the tubes.
Independently assembled tubes were mounted into the chamber prototype and its performance characteristic measured under the vacuum conditions. The results showed that both the structure and the tubes themselves normally operate. They are suitable for making a full-scale drift chamber for vacuum.
The eight-channel ASIC bipolar transresistance amplifier D0M AMPL-8.3 Alexeev, G.D.; Baturitsky, M.A.; Dvornikov, O.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2001, Letnik:
462, Številka:
3
Journal Article
Recenzirano
The eight-channel ASIC low-noise bipolar transresistance amplifier D0M Ampl-8.3 has been designed on the basis of BJT-JFET technology for gaseous wire detectors used in high-energy physics ...experiments. The amplifier has differential gain 130
mV/μA at 1
kΩ, input noise 35 and 60
nA r.m.s. at 0 and 60
pF input capacitance, respectively, leading/trailing edge 7
ns, input resistance ≈50
Ω, crosstalks −47
dB, dissipated power 160…640
mW/chip for ±3…5
V supply. The Ampl-8.3 has been accepted for upgrading the Forward Angle Muon System of the D0 experiment (Fermilab, Batavia, USA), the total number of channels is about 50,000.
We present a measurement of the top quark mass in pp collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The data were collected by the D0 experiment corresponding to ...an integrated luminosity of 9.7fb super(?1). The matrix element technique is applied to tt events in the final state containing leptons (electrons or muons) with high transverse momenta and at least two jets. The calibration of the jet energy scale determined in the lepton+jets final state of tt decays is applied to jet energies. This correction provides a substantial reduction in systematic uncertainties. We obtain a top quark mass of m sub()t173.93+ or -1.84GeV.
We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W({yields}l{nu})+{gamma} production in e{gamma} and {mu}{gamma} final states. Using ...data corresponding to an integrated luminosity of 4.2 fb{sup -1} collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp{yields}W{gamma}+X{yields}l{nu}{gamma}+X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW{gamma} couplings for data from hadron colliders: -0.4<{Delta}{kappa}{sub {gamma}<}0.4 and -0.08<{lambda}{sub {gamma}<}0.07 at the 95% C.L.
The DØ forward angle muon system front-end electronics design Alexeev, G.D.; Baturitsky, M.A.; Dvornikov, O.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2001, Letnik:
473, Številka:
3
Journal Article
Recenzirano
The 32-channel Amplifier/Discriminator Board (ADB) has been designed for Mini-Drift Tubes (MDTs) used for upgrading the DØ Forward Angle Muon System (FAMUS) (Fermilab, Batavia, USA). The ADB signal ...channels are formed by eight ASICs: four transresistance amplifiers, Ampl-8.3, and four comparators, Disc-8.3. The ADB provides operation with adjustable threshold currents 0.5–5.0
μA. Low noise (60
nA at maximal MDT capacitance 60
pF) and small firing current dispersion provide the ability for detector robust performance at low levels of anode high voltage (below 3.4
kV). Over 50,000 channels have been produced and installed in the DØ experiment.
We present a search for the standard model Higgs boson and a fermiophobic Higgs boson in the diphoton final states based on 8.2 fb{sup -1} of pp collisions at {radical}(s)=1.96 TeV collected with the ...D0 detector at the Fermilab Tevatron Collider. No excess of data above background predictions is observed and upper limits at the 95% C.L. on the cross section multiplied by the branching fraction are set which are the most restrictive to date. A fermiophobic Higgs boson with a mass below 112.9 GeV is excluded at the 95% C.L.
We report results from a search for neutral Higgs bosons produced in association with b quarks using data recorded by the D0 experiment at the Fermilab Tevatron Collider and corresponding to an ...integrated luminosity of 7.3 fb{sup -1}. This production mode can be enhanced in several extensions of the standard model (SM) such as in its minimal supersymmetric extension (MSSM) at high tan{beta}. We search for Higgs bosons decaying to tau pairs with one tau decaying to a muon and neutrinos and the other to hadrons. The data are found to be consistent with SM expectations, and we set upper limits on the cross section times branching ratio in the Higgs boson mass range from 90 to 320 GeV/c{sup 2}. We interpret our result in the MSSM parameter space, excluding tan{beta} values down to 25 for Higgs boson masses below 170 GeV/c{sup 2}.
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