C. Campagnari
A5100631809- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Medical Imaging Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Nuclear physics research studies
- Astrophysics and Cosmic Phenomena
- Heart Failure Treatment and Management
- Distributed and Parallel Computing Systems
- Cardiovascular Function and Risk Factors
- CCD and CMOS Imaging Sensors
- Nuclear Physics and Applications
- Gamma-ray bursts and supernovae
- Stochastic processes and financial applications
- Particle accelerators and beam dynamics
- Advanced Data Storage Technologies
University of California, Santa Barbara
2016-2025
University of California System
2024-2025
Institute of High Energy Physics
2010-2024
A. Alikhanyan National Laboratory
2022-2024
University of Antwerp
2024
University of California, San Diego
2019-2024
Seoul National University
2024
Northwestern University
2024
California Institute of Technology
2023
European Organization for Nuclear Research
2012-2017
We establish the existence of top quark using a 67 pb^-1 data sample Pbar-P collisions at Sqrt(s) = 1.8 TeV collected with Collider Detector Fermilab (CDF). Employing techniques similar to those we previously published, observe signal consistent t-tbar decay WW b-bbar, but inconsistent background prediction by 4.8 sigma. Additional evidence for is provided peak in reconstructed mass distribution. measure be 176 +/-8(stat) +/- 10(sys.) GeV/c^2, and production cross section 6.8 +3.6 -2.4 pb.
Searches for lepton-flavor-violating decays of a tau lepton to lighter mass and photon have been performed with the entire data set (963+/-7)x10{6} collected by BABAR detector near Upsilon(4S), Upsilon(3S) Upsilon(2S) resonances. The searches yield no evidence signals we upper limits on branching fractions B(tau{+/-}-->e{+/-}gamma)<3.3x10{-8} B(tau{+/-}-->mu{+/-}gamma)<4.4x10{-8} at 90% confidence level.
Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce light mediator, so-called photon (A′), connecting sector to standard model. We present search for reaction e+e−→γA′, A′→e+e−, μ+μ− using 514 fb−1 data collected with BABAR detector. observe no statistically significant deviations from model predictions, and we set 90% confidence level upper limits on mixing strength between at 10−4−10−3...
We present the results of a search for top quark in 19.3 pb−1 p¯p collisions at √s =1.8 TeV. The data were collected Fermilab Tevatron collider using Collider Detector (CDF). includes standard model tt¯ decays to final states eeνν¯, eμνν¯, and μμνν¯ as well e+ν+jets or μ+ν+jets. In (e,μ)+ν+jets channel we b quarks from t via secondary vertex identification semileptonic cascade c quarks. dilepton find two events with background 0.56+0.25−0.13 events. e,μ+ν+jets identified vertex, six 2.3±0.3....
We summarize a search for the top quark with Collider Detector at Fermilab (CDF) in sample of p¯p collisions √s =1.8 TeV an integrated luminosity 19.3 pb−1. find 12 events consistent either two W bosons, or boson and least one b jet. The probability that measured yield is background 0.26%. Though statistics are too limited to establish firmly existence quark, natural interpretation excess it due tt¯ production. Under this assumption, constrained fits individual mass 174±10+13−12 GeV/c2....
A precise measurement of the cross section process e+ e- to pi+ pi- (gamma) from threshold an energy 3 GeV is obtained with initial state radiation (ISR) method using 232 fb^-1 data collected BABAR detector at center-of-mass energies near 10.6 GeV. The ISR luminosity determined a study leptonic mu+ mu- gamma (gamma). leading-order hadronic contribution muon magnetic anomaly calculated pi measured 1.8 (514.1 +-2.2(stat} +-3.1(syst}) x 10^{-10}.
We present a study of $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$ production in $p\overline{p}$ collisions, at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$ with the CDF detector Fermilab. The mesons are reconstructed using their ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ decay modes. have measured inclusive cross section for both as function transverse momentum central region, $|\ensuremath{\eta}|<0.6$. also measure fraction these events...
The production and event topology of three-jet events produced in p¯p collisions at √s=1.8 TeV have been studied with the Collider Detector Fermilab Tevatron Collider. distributions angular variables (ψ∗ cosθ∗) describing energy sharing between jets (x3 x4) are found to agree well tree-level QCD calculations. These predicted different shapes for initial-state subprocesses (quark-antiquark, quark-gluon, gluon-gluon). data consistent small expected contribution from quark-antiquark initial...
A strong signal for double parton (DP) scattering is observed in a $16{\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ sample of $\overline{p}p\ensuremath{\rightarrow}\ensuremath{\gamma}/{\ensuremath{\pi}}^{0}+3\mathrm{jets}+X$ data from the CDF experiment at Fermilab Tevatron. In DP events, two separate hard scatterings take place single $\overline{p}p$ collision. We isolate large $(\ensuremath{\sim}14000\mathrm{events})$ which 53% are found to be DP. The process-independent parameter scattering,...
We have measured the fraction of $J/\ensuremath{\psi}$ mesons originating from ${\ensuremath{\chi}}_{c}$ meson decays in $p\overline{p}$ collisions at $\sqrt{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.8\mathrm{TeV}$. The fraction, for ${P}_{T}^{J/\ensuremath{\psi}}>4.0\mathrm{GeV}/c$ and $|{\ensuremath{\eta}}^{J/\ensuremath{\psi}}|<0.6$, not including contributions $b$ flavored hadrons, is...
Inclusive J/\ensuremath{\psi} and \ensuremath{\psi}(2S) production has been studied in p\ifmmode\bar\else\textasciimacron\fi{}p collisions at \ensuremath{\surd}s =1.8 TeV using 2.6\ifmmode\pm\else\textpm\fi{}0.2 ${\mathrm{pb}}^{\mathrm{\ensuremath{-}}1}$ of data taken with the Collider Detector Fermilab. The products cross section times branching fraction were measured as functions ${\mathit{P}}_{\mathit{T}}$ for...
In a sample of $471\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected with the BABAR detector at PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ collider we study rare decays $B\ensuremath{\rightarrow}{K}^{(*)}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, where ${\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ is either or ${\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. We report results on partial branching fractions and isospin...
This paper reports measurements of processes: e+e−→γKS0K±π∓, e+e−→γK+K−π0, e+e−→γϕη, and e+e−→γϕπ0. The initial-state radiated photon allows to cover the hadronic final state in energy range from thresholds up ≈4.6 GeV. overall size data sample analyzed is 232 fb−1, collected by BABAR detector running at PEP-II e+e− storage ring. From Dalitz plot analysis KS0K±π∓ state, moduli, relative phase isoscalar isovector components e+e−→KK*(892) cross section are determined. Parameters ϕ ρ...
The inclusive jet differential cross section has been measured for transverse energies, ET, from 15 to 440 GeV, in the pseudorapidity region 0.1≤|η|≤0.7. results are based on 19.5pb−1 of data collected by CDF Collaboration at Fermilab Tevatron collider. compared with QCD predictions various sets parton distribution functions. jets ET>200GeV is significantly higher than current O(αs3) perturbative calculations. Various possible explanations high- ET excess discussed.Received 25 January...
We present a study of the decays B^{0,+} --> J/psi pi^+ pi^- pi^0 K^{0,+}, using 467 10^6 BBbar pairs recorded with BABAR detector. evidence for decay mode X(3872) omega, product branching fractions B(B^+ X(3872)K^+) B(X(3872) omega) =[0.6\pm0.2\stat \pm 0.1\syst ] 10^{-5}, and B(B^0 X(3872)K^0) =[0.6\pm0.3\stat 10^{-5}. A detailed mass distribution from favors negative-parity assignment.
We report a measurement of the proton-antiproton total cross section ${\mathrm{\ensuremath{\sigma}}}_{\mathit{T}}$ at c.m.s. energies \ensuremath{\surd}s =546 and 1800 GeV. Using luminosity-independent method, we find ${\mathrm{\ensuremath{\sigma}}}_{\mathit{T}}$=61.26\ifmmode\pm\else\textpm\fi{}0.93 mb GeV 80.03\ifmmode\pm\else\textpm\fi{}2.24 =1800 In this energy range, ratio ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{el}}$/${\mathrm{\ensuremath{\sigma}}}_{\mathit{T}}$ increases from...
In a search for $B\ensuremath{\rightarrow}c\overline{c}\ensuremath{\gamma}K$ decays with the BABAR detector, where $c\overline{c}$ includes $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$, $K$ ${K}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}_{S}^{0}$, ${K}^{*}(892)$, we find evidence $X(3872)\ensuremath{\rightarrow}J/\ensuremath{\psi}\ensuremath{\gamma}$ $X(3872)\ensuremath{\rightarrow}\ensuremath{\psi}(2S)\ensuremath{\gamma}$ $3.6\ensuremath{\sigma}$ $3.5\ensuremath{\sigma}$ significance,...
We search for evidence of a light scalar boson in the radiative decays Upsilon(2S) and Upsilon(3S) resonances: Upsilon(2S,3S)-->gammaA0, A0-->mu+mu-. Such particle appears extensions standard model, where CP-odd Higgs naturally couples strongly to b quarks. find no such processes mass range 0.212 < or = mA0 9.3 GeV samples 99 x 10(6) 122 collected by BABAR detector at SLAC PEP-II B factory set stringent upper limits on effective coupling quark A0. also limit dimuon branching fraction etab...
Kinematic properties of four-jet events produced in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV have been studied using data with an integrated luminosity 325 ${\mathrm{nb}}^{\ensuremath{-}1}$ collected the Collider Detector Fermilab during 1988-1989 run. The individual jet ${p}_{T}$ spectra and angles between each pair are compared to predictions leading-order quantum chromodynamics for double gluon bremsstrahlung process good agreement is observed. In addition, a search parton...
We study the processes e+e−→2(π+π−)π0γ, 2(π+π−)ηγ, K+K−π+π−π0γ and K+K−π+π−ηγ with hard photon radiated from initial state. About 20 000, 4300, 5500, 375 fully reconstructed events, respectively, are selected 232 fb−1 of BABAR data. The invariant mass hadronic final state defines effective e+e− center-of-mass energy, so that obtained cross sections threshold to about 5 GeV can be compared corresponding direct measurements, currently available only for ηπ+π− ωπ+π− submodes e+e−→2(π+π−)π0...
We present a study of the decays B0,+→J/ψωK0,+ using 383×106 B¯¯¯B events obtained with BABAR detector at PEP-II. observe Y(3940)→J/ψω, mass 3914.6+3.8−3.4(stat)±2.0(syst) MeV/c2, and width 34+12−8(stat)±5(syst) MeV. The ratio B0 B+ decay to YK is 0.27+0.28−0.23(stat)+0.04−0.01(syst), relevant branching fractions are reported.Received 14 November 2007DOI:https://doi.org/10.1103/PhysRevLett.101.082001©2008 American Physical Society
We report the results of a search for bottomonium ground state eta_b(1S) in photon energy spectrum with sample (109 +/- 1) million Upsilon(3S) recorded at BABAR detector PEP-II B factory SLAC. observe peak E_gamma = 921.2 {+2.1} {-2.8} (stat) 2.4(syst) MeV significance 10 standard deviations. interpret observed as being due to monochromatic photons from radiative transition -> gamma eta_b(1S). This corresponds an mass $9388.9 {+3.1} {-2.3} 2.7(syst) MeV/c2. The hyperfine...
We report the results of a search for $Z(4430)^-$ decay to $J/\psi\pi^-$ or $\psi(2S)\pi^-$ in $B^{-,0}\to \jpsi\pi^- K^{0,+}$ and \psitwos \pi^- decays. The data were collected with BABAR detector at SLAC PEP-II asymmetric-energy $e^+e^-$ collider operating center mass energy 10.58 \gev, sample corresponds an integrated luminosity 413 fb$^{-1}$. Each $K\pi$ distribution exhibits clear $K^{\ast}(892)$ $K^{\ast}_2(1430)$ signals, efficiency-corrected spectrum is well-described by...