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Sökning: L773:1674 1137 OR L773:2058 6132

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1.
  • Bi, Xiao Jun, et al. (författare)
  • Chapter 5 Dark Matter and New Physics Beyond the Standard Model with LHAASO
  • 2022
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 46:3
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to reveal the nature of dark matter, it is crucial to detect its non-gravitational interactions with the standard model particles. The traditional dark matter searches focused on the so-called weakly interacting massive particles. However, this paradigm is strongly constrained by the null results of current experiments with high precision. Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale. The Large High Altitude Air Shower Observatory (LHAASO) with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale. In this document, we review the theoretical motivations and background of heavy dark matter. We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO, and present the projected sensitivities. We also review the prospects of searching for the axion-like particles, which are a kind of well motivated light pseudo-scalars, through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.
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2.
  • Morais, António P., et al. (författare)
  • What can a heavy U(1)B−L Z′ boson do to the muon (g−2)µ anomaly and to a new Higgs boson mass?
  • 2021
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 45:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The minimal U(1)B−L extension of the Standard Model (B-L-SM) offers an explanation for neutrino mass generation via a seesaw mechanism; it also offers two new physics states, namely an extra Higgs boson and a new Z′ gauge boson. The emergence of a second Higgs particle as well as a new Z′ gauge boson, both linked to the breaking of a local U(1)B−L symmetry, makes the B-L-SM rather constrained by direct searches in Large Hadron Collider (LHC) experiments. We investigate the phenomenological status of the B-L-SM by confronting the new physics predictions with the LHC and electroweak precision data. Taking into account the current bounds from direct LHC searches, we demonstrate that the prediction for the muon (g−2)µ anomaly in the B-L-SM yields at most a contribution of approximately 8.9×10−12 , which represents a tension of 3.28 standard deviations, with the current 1σ uncertainty, by means of a Z′ boson if its mass is in the range of 6.3 to 6.5 TeV, within the reach of future LHC runs. This means that the B-L-SM, with heavy yet allowed Z′ boson mass range, in practice, does not resolve the tension between the observed anomaly in the muon (g−2)µ and the theoretical prediction in the Standard Model. Such a heavy Z′ boson also implies that the minimal value for the new Higgs mass is of the order of 400 GeV.
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3.
  • Aad, G., et al. (författare)
  • Performance and calibration of quark/gluon-jet taggers using 140 fb-1 of pp collisions at √s=13 TeV with the ATLAS detector
  • 2024
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 48:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced background. This paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration, using √?=13 TeV proton–proton collision data with an integrated luminosity of 140 fb−1 collected by the ATLAS experiment. Two taggers with high performances in rejecting jets from gluon over jets from quarks are studied: one tagger is based on requirements on the number of inner-detector tracks associated with the jet, and the other combines several jet substructure observables using a boosted decision tree. A method is established to determine the quark/gluon fraction in data, by using quark/gluon-enriched subsamples defined by the jet pseudorapidity. Differences in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.
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4.
  • Aaij, R., et al. (författare)
  • Search for the doubly heavy baryon Ξ+bc decaying to J/ψΞ+c
  • 2023
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 47:9
  • Tidskriftsartikel (refereegranskat)abstract
    • A first search for the decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of and standard deviations at masses of 6571 and 6694 MeV/, respectively. Upper limits are set on the baryon production cross-section times the branching fraction relative to that of the decay at centre-of-mass energies of 8 and 13 TeV, in the and in the rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to , respectively. Upper limits are presented as a function of the mass and lifetime.
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5.
  • Aaij, R., et al. (författare)
  • Search for the rare decays W+ →Ds+ ϒ and Z →D0 ϒ at LHCb
  • 2023
  • Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 47:9
  • Tidskriftsartikel (refereegranskat)abstract
    • A search for the rare decays W+ -> D-s(+)gamma and Z -> D-0 gamma and is performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV, corresponding to an integrated luminosity of 2.0fb(-1). No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W+ -> mu(+)nu and Z ->mu(+)mu(-)decays as normalization channels. The upper limits are and at 95% confidence level for W+ -> D-s(+)gamma and Z -> D-0 gamma the and decay modes, respectively. This is the first reported search for Z -> D-0 gamma the decay, while the upper limit on the Z -> D-0 gamma branching fraction improves upon the previous best limit.
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6.
  • Ablikim, M., et al. (författare)
  • Luminosities and energies of e+e− collision data taken between √s=4.61 GeV and 4.95 GeV at BESIII
  • 2022
  • Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 46:11
  • Tidskriftsartikel (refereegranskat)abstract
    • From December 2019 to June 2021, the BESIII experiment collected approximately 5.85 fb−1 of data at center-of-mass energies between 4.61 and 4.95 GeV. This is the highest collision energy BEPCII has reached to date. The accumulated annihilation data samples are useful for studying charmonium(-like) states and charmed-hadron decays. By adopting a novel method of analyzing the production of pairs in annihilation, the center-of-mass energies are measured with a precision of 0.6 MeV. Integrated luminosities are measured with a precision of better than 1% by analyzing the events of large-angle Bhabha scattering. These measurements provide important inputs to analyses based on these data samples.
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7.
  • Ablikim, M., et al. (författare)
  • Measurement of integrated luminosities at BESIII for data samples at center-of-mass energies between 4.0 and 4.6 GeV
  • 2022
  • Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 46:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The integrated luminosities of data samples collected in the BESIII experiment in 2016-2017 at center-of-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events. The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance, offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter, which can haphazardly occur.
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8.
  • Ablikim, M., et al. (författare)
  • Measurements of the center-of-mass energies of collisions at BESIII
  • 2021
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 45:10
  • Tidskriftsartikel (refereegranskat)abstract
    • During the 2016-17 and 2018-19 running periods, the BESIII experiment collected 7.5 fb(-1) of e(+)e(-) collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV. These data samples are primarily used for the study of excited charmonium and charmoniumlike states. By analyzing the di-muon process e(+)e(-) -> (gamma ISR/FSR)mu(+)mu(-), we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV. Through a run-by-run study, we find that the center-of-mass energies were stable throughout most of the data-collection period.
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9.
  • Ablikim, M., et al. (författare)
  • Number of J/psi events at BESIII
  • 2022
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 46:7
  • Tidskriftsartikel (refereegranskat)abstract
    • Using inclusive decays of J/psi, a precise determination of the number of J/psi events collected with the BESIII detector was performed. For the two data sets taken in 2009 and 2012, the numbers of J/psi events were recalculated (224.0 +/- 1.3) x 10(6) (1088.5 +/- 4.4) x 10(6), respectively; these numbers are in good agreement with the previous measurements. For the J/psi sample taken in 2017-2019, the number of events was determined to be (8774 .0 +/- 39 .4) x 10(6). The total number of J/psi events collected with the BESIII detector was determined to be (10087 +/- 44) x 10(6), where the uncertainty is dominated by systematic effects, and the statistical uncertainty is negligible.
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10.
  • Ablikim, M., et al. (författare)
  • Observation of e(+) e(-) -> pp(p)over-bar(p)over-bar pi(-) +c.c (*)
  • 2023
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 47:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Using data taken at 29 center-of-mass energies between 4.16 and 4.70 GeV with the BESIII detector at the Beijing Electron Positron Collider corresponding to a total integrated luminosity of approximately 18.8, the process e(+)e(-) -> pp (p) over bar(p) over bar pi(-) +c.c is observed for the first time with a statistical significance of 11.5 sigma. The average Born cross sections in the energy ranges of (4.160, 4.380) GeV, (4.400, 4.600) GeV and (4.610, 4.700) GeV are measured to be (21.5 +/- 5.7 +/- 1.2) fb, fb and (59.0 +/- 9.4 +/- 3.2)fb, respectively, where the first uncertainties are statistical and the second are systematic. The line shapes of the (p) over bar(n) over bar and pp pi(-) invariant mass spectra are consistent with phase space distributions, indicating that no hexaquark or di-baryon state is observed.
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11.
  • Ablikim, M., et al. (författare)
  • Observation of the Y(4230) and a new structure in e(+)e(-) -> K+ K- J/psi
  • 2022
  • Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 46:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross sections of e(+)e(-) -> K+K- J/psi at center-of-mass energies from 4.127 to 4.600 GeV are measured based on 15.6 fb(-1) data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in the line shape of the cross sections. The mass and width of the first structure are measured to be (4225.3 +/- 2.3 +/- 21.5) MeV and (72.9 +/- 6.1 +/- 30.8) MeV, respectively. They are consistent with those of the established Y(4230). The second structure is observed for the first time with a statistical significance greater than 8 sigma, denoted as Y(4500). Its mass and width are determined to be (4484.7 +/- 13.3 +/- 24.1) MeV and (111.1 +/- 30.1 +/- 15.2) MeV, respectively. The first presented uncertainties are statistical and the second ones are systematic. The product of the electronic partial width with the decay branching fraction Gamma(Y(4230) -> e(+)e(-))B(Y(4230) -> K+ K- J/psi) is reported.
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12.
  • Ablikim, M., et al. (författare)
  • Search for hidden-charm tetraquark with strangeness in e(+) e(-) -> K+ D-s(*-) D-*0 +c.c. (*)
  • 2023
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 47:3
  • Tidskriftsartikel (refereegranskat)abstract
    • We report a search for a heavier partner of the recently observed Z(cs) (3985)(-) state, denoted as Z '(-)(cs), in the process e(+)e(-) -> K+Ds*- D(*0+)c.c., based on e(+)e(-)collision data collected at the center-of-mass energies of root s =4.661,4.682 and 4.699 GeV with the BESIII detector. The Z '(-)(cs) is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark. A partial-reconstruction technique is used to isolate recoil-mass spectra, which are probed for a potential contribution from Z '(-)(cs) -> D-s(*-) D-*0 (c.c). We find an excess of Z '(-)(cs) -> D-s(*-) D-*0 (c.c) candidates with a significance of 2.1 sigma after considering systematic uncertainties, at a mass of(4.123.5 +/- 0.7(stat.) +/- 4.7(syst.) ) MeV/c(2.) As the data set is limited in size, the upper limits are evaluated at the 90% confidence level on the product of the Born cross sections (sigma(Born)) and the branching fraction (B) of Z '(-)(cs) -> D-s(*-) D-*0 under different assumptions of the Z '(-)(cs) mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies. The upper limits of sigma(Born) are found to be at the level of O(1) pb at each energy. Larger data samples are needed to confirm Z '(-)(cs) the state and clarify its nature in the coming years.
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13.
  • Ablikim, M., et al. (författare)
  • Search for the weak decay ψ(3686) → Λ+c∑‾-+c.c.*
  • 2023
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 47:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Using events collected with the BESIII detector, we perform the first search for the weak baryonic decay . The analysis procedure is optimized using a blinded method. No significant signal is observed, and the upper limit on the branching fraction () of is set as at the 90% confidence level.
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14.
  • Ablikim, M., et al. (författare)
  • Study of BESIII trigger efficiencies with the 2018 J/psi data
  • 2021
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 45:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Using a dedicated data sample taken in 2018 on the J/psi peak, we perform a detailed study of the trigger efficiencies of the BESIII detector. The efficiencies are determined from three representative physics processes, namely Bhabha scattering, dimuon production and generic hadronic events with charged particles. The combined efficiency of all active triggers approaches 100% in most cases, with uncertainties small enough not to affect most physics analyses.
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15.
  • Addazi, Andrea, et al. (författare)
  • Time-crystal ground state and production of gravitational waves from QCD phase transition
  • 2019
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 43:6
  • Tidskriftsartikel (refereegranskat)abstract
    • We propose a novel mechanism for the production of gravitational waves in the early Universe that originates from the relaxation processes induced by the QCD phase transition. While the energy density of the quark-gluon mean-field is monotonously decaying in real time, its pressure undergoes a series of violent oscillations at the characteristic QCD time scales that generate a primordial multi-peaked gravitational waves signal in the radio frequencies' domain. The signal is an echo of the QCD phase transition that is accessible by planned measurements at the FAST and SKA telescopes.
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16.
  • Czakon, Micha&lstrok, et al. (författare)
  • Top quark pair production at complete NLO accuracy with NNLO+NNLL′ corrections in QCD
  • 2020
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 44:8
  • Tidskriftsartikel (refereegranskat)abstract
    • We describe predictions for top quark pair differential distributions at hadron colliders, by combining the next-to-next-to-leading order quantum chromodynamics calculations and next-to-leading order electroweak corrections with double resummation at the next-to-next-to-leading logarithmic accuracy of threshold logarithms and small-mass logarithms. To the best of our knowledge, this is the first study to present such a combination, which incorporates all known perturbative information. Numerical results are presented for the invariant-mass distribution, transverse-momentum distribution, and rapidity distributions.
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17.
  • Olive, K. A., et al. (författare)
  • REVIEW OF PARTICLE PHYSICS Particle Data Group
  • 2014
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 38:9
  • Forskningsöversikt (refereegranskat)abstract
    • The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,283 new measurements from 899 Japers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as heavy neutrinos, supersymmetric and technicolor particles, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Supersymmetry, Extra Dimensions, Particle Detectors, Probability, and Statistics. Among the 112 reviews are many that are new or heavily revised including those on: Dark Energy, Higgs Boson Physics, Electroweak Model, Neutrino Cross Section Measurements, Monte Carlo Neutrino Generators, Top Quark, Dark Matter, Dynamical Electroweak Symmetry Breaking, Accelerator Physics of Colliders, High-Energy Collider Parameters, Big Bang Nucleosynthesis, Astrophysical Constants and Cosmological Parameters.
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18.
  • Aaij, R., et al. (författare)
  • Search for the doubly heavy baryons Ω0bc and Ξ0bc decaying to Λ+c Π- and Ξ+cΠ-
  • 2021
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 45:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The first search for the doubly heavy Omega(0)(bc) baryon and a search for the Xi(0)(bc) baryon are performed using collision data collected via the experiment from 2016 to 2018 at a centre-of-mass energy of, corresponding to an integrated luminosity of 5.2 fb(-1). The baryons are reconstructed via their decays to Lambda(+)(-)(c)(pi) and Xi(+)(c)pi(-). No significant excess is found for invariant masses between 6700 and 7300 MeV/c(2), in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c. Upper limits are set on the ratio of the Omega(0)(bc) and Xi(0)(bc) production cross-section times the branching fraction to Lambda(+)(c)pi(-)(Xi(+)(c)pi(-)) relative to that of the Lambda(0)(b)(Xi(0)(b)) baryon, for different lifetime hypotheses, at 95% confidence level. The upper limits range from 0.5x10(-4) to 2.5x10(-4) for the Omega(0)(bc) -> Lambda(+)(c)pi(-) (Xi(0)(bc) -> Lambda(+)(c)pi(-)) decay, pending on the considered mass and lifetime of the Omega(0)(bc) (Xi(0)(bc)) baryon.
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19.
  • Ablikim, M., et al. (författare)
  • Observations of the Cabibbo-Suppressed decays Λ+c → nπ+ π0, nπ+π-π+ and the Cabibbo-Favored decay Λ+c → nK-π+π+*
  • 2023
  • Ingår i: Chinese Physics C. - : Institute of Physics Publishing (IOPP). - 1674-1137 .- 2058-6132. ; 47:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Using electron-positron annihilation data samples corresponding to an integrated luminosity of 4.5 fb, collected by the BESIII detector in the energy region between and , we report the first observations of the Cabibbo-suppressed decays , , and the Cabibbo-favored decay with statistical significances of , , and , respectively. The branching fractions of these decays are measured to be %, $ 0.03)$%, and %, where the first uncertainties are statistical and the second are systematic. We find that the branching fraction of the decay is about one order of magnitude higher than that of .
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20.
  • Ablikim, M., et al. (författare)
  • Evidence for the decays of Lambda(+)(C) -> Sigma(+) eta and Sigma(+) eta '
  • 2019
  • Ingår i: Chinese Physics C. - : IOP PUBLISHING LTD. - 1674-1137 .- 2058-6132. ; 43:8
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the hadronic decays of Lambda(+)(C) to the final states Sigma(+) eta and Sigma(+) eta', using an e(+) e(-) annihilation data sample of 567 pb(-1) taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays Lambda(+)(C) -> Sigma(+) eta and Sigma(+) eta' with statistical significance of and, respectively. Normalizing to the reference decays Lambda(+)(C) -> Sigma(+) pi(0) and Sigma(+) omega, we obtain the ratios of the branching fractions B(Lambda(+)(C) -> Sigma(+) eta)/B(Lambda(+)(C) -> Sigma(+) pi(0)) and B(Lambda(+)(C) -> Sigma(+) eta')/B(Lambda(+)(C) -> Sigma(+) omega) to be 0.35 +/- 0.16 +/- 0.02 and 0.86 +/- 0.34 +/- 0.04, respectively. The upper limits at the 90% confidence level are set to be B(Lambda(+)(C) -> Sigma(+) eta)/B(Lambda(+)(C) -> Sigma(+) pi(0)) < 0.58 and B(Lambda(+)(C) -> Sigma(+) eta')/B(Lambda(+)(C) -> Sigma(+) omega) < 1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(Lambda(+)(C) -> Sigma(+) eta) = (0.41 +/- 0.19 +/- 0.05)% (<0.68%) and B(Lambda(+)(C) -> Sigma(+) eta') = (1.34 +/- 0.53 +/- 0.19)% (<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of Lambda(+)(C) -> Sigma(+) eta is consistent with the previous measurement, and the branching fraction of Lambda(+)(C) -> Sigma(+) eta' is measured for the first time.
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21.
  • Ablikim, M., et al. (författare)
  • Future Physics Programme of BESIII *
  • 2020
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 44:4
  • Tidskriftsartikel (refereegranskat)abstract
    • There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESIII and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESIII, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESIII during the remaining operation period of BEPCII. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCII to higher luminosity.
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22.
  • Ablikim, M., et al. (författare)
  • Observation of e(+)e(-)-> D-s(+)(D)over-bar(()*()0) K- and study of the P-wave D-s mesons
  • 2019
  • Ingår i: Chinese Physics C. - : IOP PUBLISHING LTD. - 1674-1137 .- 2058-6132. ; 43:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Studies of e(+)e(-)-> D-s(+)(D) over bar (()*K-)0(-) and the p-wave charmed-strange mesons are performed based on an e(+)e(-) collision data sample corresponding to an integrated luminosity of 567 pb(-1) collected with the BESIII detector at root s = 4.600 GeV. The processes of e(+)e(-)-> D-s(+)(D ) over bar*K-0(-) and D-s(+)(D ) over bar K-0(-) are observed for the first time and are found to be dominated by the modes Ds+Ds1 (2536)(-) and Ds(+)Ds*(s2) (2573)(-), respectively. The Born cross sections are measured to be sigma(B)(e(+)e( -)-> D-s(+)(D ) over bar K-*0(-) (10.1 +/- 2.3 +/- 0.8) pb and D-s(+)(D ) over bar K-0(-) = (19.4 +/- 2.3 +/- 1.6) pb, and the products of Born cross section and the decay branching fraction are measured to be sigma(B)(e(+)e( -)-> Ds+Ds1(2536)(-)+c.c).B(D-s1(2536)(-) = ( 7.5 +/- 1.8 +/- 0.7) pb and sigma(B)(e(+)e(-)-> Ds+Ds1+(2573)(-)c.c.). B(D-s1(2573)(-)-> (D ) over bar*K-0(-)) = (19.7 +/- 2.9 +/- 2.0) pb. For the D-s1(2536)(-) and D-s2(2573)(-) mesons, the masses and widths are measured to be M(D-s1(2536)(-)) = (2537.7 +/- 0.5 +/- 3.1) MeV/c(2), Gamma(D-s1(2536)(-)) = (1.7 +/- 1.2 +/- 0.6)MeV, and M(D-s2*(2573)(-)) = (2570.7 +/- 2.0 +/- 1.7) MeV/c(2), Gamma(D-s2(2573)(-)) = (17.2 +/- 3.6 +/- 1.1) MeV. The spin-parity of the D-s2*(2573)(-) meson is determined to be J(P) = 2(+). In addition, the processes e(+)e(-)-> D-s(+)(D ) over bar*K-0(-) are searched for using the data samples taken at four (two) center-of-mass energies between 4.416 (4.527) and 4.575 GeV, and upper limits at the 90% confidence level on the cross sections are determined.
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23.
  • An, Haipeng, et al. (författare)
  • A unique gravitational wave signal from phase transition during inflation*
  • 2022
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 46:10
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the properties of gravitational wave (GW) signals produced by first-order phase transitions during the inflation era. We show that the power spectrum of a GW oscillates with its wave number. This signal can be observed directly by future terrestrial and spatial GW detectors and through the B-mode spectrum in the CMB. This oscillatory feature of the GW is generic for any approximately instantaneous sources occurring during inflation and is distinct from the GW from phase transitions after inflation. The details of the GW spectrum contain information about the scale of the phase transition and the later evolution of the universe.
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24.
  • Schönning, Karin, 1978-, et al. (författare)
  • Production and decay of polarized hyperon-antihyperon pairs
  • 2023
  • Ingår i: Chinese Physics C. - : Institute of Physics (IOP). - 1674-1137 .- 2058-6132. ; 47:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Polarized hyperon-antihyperon pairs shed light on various unresolved puzzles in contemporary physics: How the strong interaction confines quarks into hadrons, how accurately the Standard Model describes microcosmos and even why our universe consists of so much more matter than antimatter. Thanks to their weak, parity violating decays, hyperons reveal their spin properties. This can be exploited e.g. the decomposition of the electromagnetic structure of hyperons, precision tests of flavour symmetry and searches for CP violation. At the BESIII experiment at BEPC-II, Beijing, China, hyperon-antihyperon pairs can be produced in abundance. Recently collected large data samples have triggered the development of new methods that provide unprecedented precision and a plethora of new results have emerged. When applied at future high-intensity facilities like PANDA and STCF, precision physics will be taken to a new level which can contribute to the solution to the aforementioned puzzles.
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25.
  • Ablikim, M., et al. (författare)
  • Determination of the number of J/psi events with inclusive J/psi decays
  • 2017
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 41:1
  • Tidskriftsartikel (refereegranskat)abstract
    • A measurement of the number of J/psi events collected with the BESIII detector in 2009 and 2012 is performed using inclusive decays of the J/psi. The number of J/psi events taken in 2009 is recalculated to be (223.7 +/- 1.4) x 10(6), which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESIII software. The number of J/psi events taken in 2012 is determined to be (1086.9 +/- 6.0) x 10(6). In total, the number of J/psi events collected with the BESIII detector is measured to be (1310.6 +/- 7.0) x 10(6), where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.
  •  
26.
  • Ablikim, M., et al. (författare)
  • Determination of the number of ψ(3686) events at BESIII
  • 2018
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 42:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The numbers of psi(3686) events accumulated by the BESIII detector for the data taken during 2009 and 2012 are determined to be (107.0 +/- 0.8)x10(6) and (341.1 +/- 2.1)x10(6), respectively, by counting inclusive hadronic events, where the uncertainties are systematic and the statistical uncertainties are negligible. The number of events for the sample taken in 2009 is consistent with that of the previous measurement. The total number of psi(3686) events for the two data taking periods is (448.1 +/- 2.9) x 10(6).
  •  
27.
  • Ablikim, M., et al. (författare)
  • Evidence for e(+)e(-)->gamma chi c1,2 at center-of-mass energies from 4.009 to 4.360 GeV
  • 2015
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 39:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Using data samples collected at center-of-mass energies of root s=4.009, 4.230, 4.260, and 4.360 GeV with the BESIII detector operating at the BEPCII collider, we perform a search for the process e(+)e(-)->gamma chi(cJ) (J=0, 1, 2) and find evidence for e(+)e(-)->gamma chi(c1) and e(+)e(-)->gamma chi(c2) with statistical significances of 3.0 sigma and 3.4 sigma, respectively. The Born cross sections sigma(B)(e(+)e(-)->gamma chi(cJ)), as well as their upper limits at the 90% confidence level (C.L.) are determined at each center-of-mass energy.
  •  
28.
  • Ablikim, M., et al. (författare)
  • Luminosity measurements for the R scan experiment at BESIII
  • 2017
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 41:6
  • Tidskriftsartikel (refereegranskat)abstract
    • By analyzing the large-angle Bhabha scattering events e+e- → (γ)e+e- and diphoton events e+e- → (γ)γγ for the data sets collected at center-of-mass (c.m.) energies between 2.2324 and 4.5900 GeV (131 energy points in total) with the upgraded Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider (BEPCII), the integrated luminosities have been measured at the different c.m. energies, individually. The results are important inputs for the R value and J/ψ resonance parameter measurements.
  •  
29.
  • Ablikim, M., et al. (författare)
  • Measurement of e(+)e(-) -> D(D)over-bar cross sections at the psi(3770) resonance
  • 2018
  • Ingår i: Chinese Physics C. - : IOP PUBLISHING LTD. - 1674-1137 .- 2058-6132. ; 42:8
  • Tidskriftsartikel (refereegranskat)abstract
    • We report new measurements of the cross sections for the production of D (D) over bar final states at the psi(3770) resonance. Our data sample consists of an integrated luminosity of 2.93 fb(-1) of e(+)e(-) annihilation data produced by the BEPCII collider and collected and analyzed with the BESIII detector. We exclusively reconstruct three D-0 and six D+ hadronic decay modes and use the ratio of the yield of fully reconstructed D (D) over bar events ("double tags") to the yield of all reconstructed D or (D) over bar mesons ("single tags") to determine the number of D-0(D) over bar (0) and D+D- events, benefiting from the cancellation of many systematic uncertainties. Combining these yields with an independent determination of the integrated luminosity of the data sample, we find the cross sections to be sigma(e(+)e(-) -> D-0(D) over bar (0)(-) )=(3.615 +/- 0.010 +/- 0.038) nb and sigma(e(+)e(-) -> D+D-)=(2.830 +/- 0.011 +/- 0.026) nb, where the uncertainties are statistical and systematic, respectively.
  •  
30.
  • Ablikim, M., et al. (författare)
  • Measurement of integrated luminosity and center-of-mass energy of data taken by BESIII at √s=2.125 GeV
  • 2017
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 41:11
  • Tidskriftsartikel (refereegranskat)abstract
    • To study the nature of the state Y (2175), a dedicated data set of e(+)e(-) collision data was collected at the center-of-mass energy of 2.125 GeV with the BESIII detector at the BEPCII collider. By analyzing large-angle Bhabha scattering events, the integrated luminosity of this data set is determined to be 108.49 +/- 0.02 +/- 0.85 pb(-1), where the first uncertainty is statistical and the second one is systematic. In addition, the center-of-mass energy of the data set is determined with radiative dimuon events to be 2126.55 +/- 0.03 +/- 0.85 MeV, where the first uncertainty is statistical and the second one is systematic.
  •  
31.
  • Ablikim, M., et al. (författare)
  • Measurement of the absolute branching fraction of D+ → K̅0 e+νe via K̅0 → π 0 π 0
  • 2016
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 40:11
  • Tidskriftsartikel (refereegranskat)abstract
    • By analyzing 2.93 fb(-1) data collected at the center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of the semileptonic decay D+ -> (K) over bar (0)e(+)nu(e) to be B(D (+) -> (K) over bar (0)e(+)nu(e)) = (8.59 +/- 0.14 +/- 0.21)% using (K) over bar (0) -> K-S(0) -> pi(0) pi(0), where the first uncertainty is statistical and the second systematic. Our result is consistent with previous measurements within uncertainties..
  •  
32.
  • Ablikim, M., et al. (författare)
  • Measurement of the center-of-mass energies at BESIII via the di-muon process
  • 2016
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 40:6
  • Tidskriftsartikel (refereegranskat)abstract
    • From 2011 to 2014, the BESIII experiment collected about 5 fb$^{-1}$ data at center-of-mass energies around 4 GeV for the studies of the charmonium-like and higher excited charmonium states. By analyzing the di-muon process $e^{+}e^{-}\rightarrow\gamma_{\rm ISR/FSR}\mu^{+}\mu^{-}$, the center-of-mass energies of the data samples are measured with a precision of 0.8 MeV. The center-of-mass energy is found to be stable for most of time during the data taking.
  •  
33.
  • Ablikim, M., et al. (författare)
  • Measurement of the integrated Luminosities of cross-section scan data samples around the psi(3770) mass region
  • 2018
  • Ingår i: Chinese Physics C. - : SCIENCE PRESS. - 1674-1137 .- 2058-6132. ; 42:6
  • Tidskriftsartikel (refereegranskat)abstract
    • To investigate the nature of the psi(3770) resonance and to measure the cross section for e(+)e(-) -> D (D) over bar, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16 +/- 0.04 +/- 0.61 pb(-1), where the first uncertainty is statistical and the second systematic.
  •  
34.
  •  
35.
  • Fang, Shuang-shi, et al. (författare)
  • An overview of eta and eta ' decays at BESIII
  • 2018
  • Ingår i: Chinese Physics C. - : IOP PUBLISHING LTD. - 1674-1137 .- 2058-6132. ; 42:4
  • Forskningsöversikt (refereegranskat)abstract
    • The world's largest sample of J/psi) events, 1.31 billion events accumulated at the BESIII detector, provides a unique opportunity to investigate eta and eta' physics via two-body J/psi radiative or hadronic decays. For many eta' decay channels the low background data samples are up to three orders of magnitude larger than collected in any previous experiment. Here we review the most significant results on eta and eta' obtained at BESIII so far. The analyses range from detailed studies of common decay dynamics, observations of new radiative and Dalitz decays, and searches for rare/forbidden decays with sensitivity up to B similar to 10(-5). Finally, prospects of forthcoming runs at the J/psi peak for eta and eta' physics are discussed.
  •  
36.
  • Patrignani, C., et al. (författare)
  • REVIEW OF PARTICLE PHYSICS : Particle Data Group
  • 2016
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 40:10
  • Tidskriftsartikel (refereegranskat)abstract
    • The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,062 new measurements from 721 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 117 reviews are many that are new or heavily revised, including new reviews on Pentaquarks and Inflation. The complete Review is published online in a journal and on the website of the Particle Data Group (http://pdg.lbl.gov). The printed PDG Book contains the Summary Tables and all review articles but no longer includes the detailed tables from the Particle Listings. A Booklet with the Summary Tables and abbreviated versions of some of the review articles is also available.
  •  
37.
  • Wang, Yan-Zhao, et al. (författare)
  • Tensor force effect on the exotic structure of neutron-rich Ca isotopes*
  • 2019
  • Ingår i: Chinese Physics C. - : IOP PUBLISHING LTD. - 1674-1137 .- 2058-6132. ; 43:11
  • Tidskriftsartikel (refereegranskat)abstract
    • The structure of neutron-rich Ca isotopes is studied in the spherical Skyrme-Hartree-Fock-Bogoliubov (SHFB) approach with SLy5, SLy5+T, and 36 sets of TIJ parametrizations. The calculated results are compared with the available experimental data for the average binding energies, two-neutron separation energies and charge radii. It is found that the SLy5+T, T31, and T32 parametrizations reproduce best the experimental properties, especially the neutron shell effects at N = 20, 28 and 32, and the recently measured two-neutron separation energy of Ca-56. The calculations with the SLy5+T and T31 parametrizations are extended to isotopes near the neutron drip line. The neutron giant halo structure in the very neutron-rich Ca isotopes is not seen with these two interactions. However, depleted neutron central densities are found in these nuclei. By analyzing the neutron mean-potential, the reason for the bubble-like structure formation is given.
  •  
38.
  • Zheng, S., et al. (författare)
  • Alignments in the nobelium isotopes
  • 2009
  • Ingår i: Chinese Physics C. - BEIJING : CHINESE PHYSICAL SOC. - 1674-1137 .- 2058-6132. ; 33:2, s. 107-109
  • Tidskriftsartikel (refereegranskat)
  •  
39.
  • Venanzoni, G., et al. (författare)
  • Status of KLOE-2
  • 2010
  • Ingår i: Chinese Physics C. - 1674-1137 .- 2058-6132. ; 34:6, s. 918-
  • Tidskriftsartikel (refereegranskat)abstract
    • In a few months the KLOE-2 detector is expected to start data taking at the upgraded DAΊNE ##IMG## [http://ej.iop.org/icons/Entities/phi.gif] phi -factory of INFN Laboratori Nazionali di Frascati. It aims to collect 25 fb −1 at the ##IMG## [http://ej.iop.org/icons/Entities/phi.gif] phi (1020) peak, and about 5 fb −1 in the energy region between 1 and 2.5 GeV. We review the status and physics program of the project.
  •  
40.
  • Qi, Chong, 1983-, et al. (författare)
  • Shell-model studies of isomeric states in Fe-51,Fe-52,Fe-53
  • 2008
  • Ingår i: Chinese Physics C. - 1674-1137 .- 2058-6132. ; 32, s. 112-115
  • Tidskriftsartikel (refereegranskat)abstract
    • The yrast bands of (51,52,53)Fe have been studied with a microscopical effective Hamiltonian derived from the charge-dependent Bonn NN potential. Calculations obtain satisfactory agreements with experimental data, reproducing the observed isomeric states. The possible origins of the isomers are discussed.
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41.
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42.
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43.
  • Chen, Shuang, et al. (författare)
  • Quantitative measurement of hydroxyl radical (OH) concentration in premixed flat flame by combining laser-induced fluorescence and direct absorption spectroscopy
  • 2016
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 1674-1056. ; 25:10
  • Tidskriftsartikel (refereegranskat)abstract
    • An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence (LIF) methods is developed to quantitatively measure the concentrations of hydroxyl in CH4/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.
  •  
44.
  • Briscoe, W. J., et al. (författare)
  • Nuclear physics program at MAX-lab
  • 2009
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 0899-9996 .- 1674-1137. ; 33:12, s. 1159-1166
  • Konferensbidrag (refereegranskat)abstract
    • The upgrade of the MAX-lab Injector and the construction of MAX III, provided the opportunity for upgrading the tagged-photon facility and thus lead to the possibility of more extensive program in nuclear physics research This upgrade increased the injected electron energy to all eventual maximum of 250 MeV and allows for the extraction of electrons from the MAX I ring operated in the stretcher mode The first stretched bean was delivered in September 2005. The tagged-photon facility was commissioned in parallel with the commissioning of new experimental equipment. The PAC approved experimental program is current in progress, including measurement of pion photoproduction below the Delta(1232) The efforts at the tagged photon-facility are pursed within all international collaboration with around fifty members
  •  
45.
  • Patrignani, C. (författare)
  • Review of Particle Physics
  • 2016
  • Ingår i: Chinese Physics C. - : IOP Publishing. - 1674-1137. ; C40:10, s. 100001-100001
  • Forskningsöversikt (refereegranskat)
  •  
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