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Searching for axionlike particles at future <math><mi>e</mi><mi>p</mi></math> colliders
https://repo.scoap3.org/record/33867
We explore the possibility of searching for axionlike particle (ALP) at future ep colliders via the subprocess e−γ→e−a→e−γγ. Sensitivities to the effective ALP-photon coupling gaγγ for its mass in the range of 10 GeV<Ma<3 TeV are obtained for the LHeC and its high-energy upgrade, FCC-eh. Comparing to existing bounds on the ALP free parameters, we find that the bounds given by ep colliders are competitive and complementary to other colliders.Yue, Chong-XingWed, 17 Jul 2019 00:16:06 GMThttps://repo.scoap3.org/record/33867APS2019-07-16Studies of Beauty Suppression via Nonprompt <math><mrow><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math> Mesons in Pb-Pb Collisions at <math><mrow><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>5.02</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math>
https://repo.scoap3.org/record/33752
The transverse momentum spectra of D0 mesons from b hadron decays are measured at midrapidity (|y|<1) in pp and Pb-Pb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The D0 mesons from b hadron decays are distinguished from prompt D0 mesons by their decay topologies. In Pb-Pb collisions, the B→D0 yield is found to be suppressed in the measured pT range from 2 to 100 GeV/c as compared to pp collisions. The suppression is weaker than that of prompt D0 mesons and charged hadrons for pT around 10 GeV/c. While theoretical calculations incorporating partonic energy loss in the quark-gluon plasma can successfully describe the measured B→D0 suppression at higher pT, the data show an indication of larger suppression than the model predictions in the range of 2<pT<5 GeV/c.Sirunyan, A. M.Wed, 10 Jul 2019 00:16:23 GMThttps://repo.scoap3.org/record/33752APS2019-07-09Search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at 13 TeV
https://repo.scoap3.org/record/33658
Results are reported of a search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb −1 collected at a center-of-mass energy of 13 TeV using the CMS detector. The results are interpreted in the context of models of gauge-mediated supersymmetry breaking. Production cross section limits are set on gluino and squark pair production in this framework. Gluino masses below 1.86 TeV and squark masses below 1.59 TeV are excluded at 95% confidence level.Sirunyan, A.Wed, 03 Jul 2019 18:32:15 GMThttps://repo.scoap3.org/record/336582019-06-28Observation of <math><mrow><mi>ψ</mi><mo>(</mo><mn>3686</mn><mo>)</mo><mo>→</mo><mi>p</mi><mover><mrow><mi>p</mi></mrow><mrow><mo>¯</mo></mrow></mover><mi>ϕ</mi></mrow></math>
https://repo.scoap3.org/record/33597
Using a data sample of 4.48×108 ψ(3686) events collected with the BESIII detector, we present a first observation of ψ(3686)→pp¯ϕ, and we measure its branching fraction to be [6.06±0.38(stat)±0.48(syst)]×10−6. In contrast to the earlier discovery of a threshold enhancement in the pp¯-mass spectrum of the channel J/ψ→γpp¯, denoted as X(pp¯), we do not find a similar enhancement in ψ(3686)→pp¯ϕ. An upper limit of 1.82×10−7 at the 90% confidence level on the branching fraction of ψ(3686)→X(pp¯)ϕ→pp¯ϕ is obtained.Ablikim, M.Thu, 27 Jun 2019 16:16:07 GMThttps://repo.scoap3.org/record/33597APS2019-06-27Measurement of electroweak WZ boson production and search for new physics in WZ + two jets events in pp collisions at s=13TeV
https://repo.scoap3.org/record/33576
A measurement of WZ electroweak (EW) vector boson scattering is presented. The measurement is performed in the leptonic decay modes WZ→ℓνℓ′ℓ′ , where ℓ,ℓ′=e,μ . The analysis is based on a data sample of proton-proton collisions at s=13 TeV at the LHC collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb −1 . The WZ plus two jet production cross section is measured in fiducial regions with enhanced contributions from EW production and found to be consistent with standard model predictions. The EW WZ production in association with two jets is measured with an observed (expected) significance of 2.2 (2.5) standard deviations. Constraints on charged Higgs boson production and on anomalous quartic gauge couplings in terms of dimension-eight effective field theory operators are also presented.Sirunyan, A.M.Wed, 26 Jun 2019 13:51:33 GMThttps://repo.scoap3.org/record/335762019-08-10Emergence of a Complete Heavy-Quark Spin Symmetry Multiplet: Seven Molecular Pentaquarks in Light of the Latest LHCb Analysis
https://repo.scoap3.org/record/33515
A recent analysis by the LHCb Collaboration suggests the existence of three narrow pentaquarklike states—the Pc(4312), Pc(4440), and Pc(4457)—instead of just one in the previous analysis [the Pc(4450)]. The closeness of the Pc(4312) to the D¯Σc threshold and the Pc(4440) and Pc(4457) to the D¯*Σc threshold suggests a molecular interpretation of these resonances. We show that these three pentaquarklike resonances can be naturally accommodated in a contact-range effective field theory description that incorporates heavy-quark spin symmetry. This description leads to the prediction of all the seven possible S-wave heavy antimeson-baryon molecules [that is, there should be four additional molecular pentaquarks in addition to the Pc(4312), Pc(4440), and Pc(4457)], providing the first example of a heavy-quark spin symmetry molecular multiplet that is complete. If this is confirmed, it will not only give us an impressive example of the application of heavy-quark symmetries and effective field theories in hadron physics, it will also uncover a clear and powerful ordering principle for the molecular spectrum, reminiscent of the SU(3)-flavor multiplets to which the light hadron spectrum conforms.Liu, Ming-ZhuFri, 21 Jun 2019 16:16:24 GMThttps://repo.scoap3.org/record/33515APS2019-06-21Two-mediator dark matter models and cosmic electron excess
https://repo.scoap3.org/record/33505
The cosmic electron energy spectrum recently observed by the DAMPE experiment exhibits two interesting features, including a break around 0.9 TeV and a sharp resonance near 1.4 TeV. In this analysis, we propose a dark matter explanation to both exotic features seen by DAMPE. In our model, dark matter annihilates in the galaxy via two different channels that lead to both a narrow resonance spectrum near 1.4 TeV and electron excess events over an extended energy range thus generating the break structure around TeV. The two annihilation channels are mediated by two gauge bosons that interact both with dark matter and with the standard model fermions. Dark matter annihilations through the s-channel process mediated by the heavier boson produce monoen-ergetic electron-positron pairs leading to the resonance excess. The lighter boson has a mass smaller than the dark matter such that they can be on-shell produced in dark matter annihilations in the galaxy; the lighter bosons in the final state subsequently decay to generate the extended excess events due to the smeared electron energy spectrum in this process. We further analyze constraints from various experiments, including HESS, Fermi, AMS, and LHC, to the parameter space of the model where both excess events can be accounted for. In order to interpret the two new features in the DAMPE data, dark matter annihilation cross sections in the current galaxy are typically much larger than the canonical thermal cross section needed for the correct dark matter relic abundance. This discrepancy, however, is remedied by the nonperturbative Sommerfeld enhancement because of the existence of a lighter mediator in the model.Liu, XuewenFri, 21 Jun 2019 08:34:19 GMThttps://repo.scoap3.org/record/335052019-06-20Search for the associated production of the Higgs boson and a vector boson in proton-proton collisions at s $$ \sqrt{s} $$ = 13 TeV via Higgs boson decays to τ leptons
https://repo.scoap3.org/record/33497
A search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to a pair of τ leptons is performed. A data sample of proton-proton collisions collected at s $$ \sqrt{s} $$ = 13 TeV by the CMS experiment at the CERN LHC is used, corresponding to an integrated luminosity of 35.9 fb −1 . The signal strength is measured relative to the expectation for the standard model Higgs boson, yielding μ = 2.5 − 1.3 + 1.4 . These results are combined with earlier CMS measurements targeting Higgs boson decays to a pair of τ leptons, performed with the same data set in the gluon fusion and vector boson fusion production modes. The combined signal strength is μ = 1.24 − 0.27 + 0.29 (1.00 − 0.23 + 0.24 expected), and the observed significance is 5.5 standard deviations (4.8 expected) for a Higgs boson mass of 125 GeV.Sirunyan, A.Thu, 20 Jun 2019 16:33:31 GMThttps://repo.scoap3.org/record/334972019-06-19Search for an exotic decay of the Higgs boson to a pair of light pseudoscalars in the final state with two muons and two b quarks in pp collisions at 13 TeV
https://repo.scoap3.org/record/33444
A search for exotic decays of the Higgs boson to a pair of light pseudoscalar particles a1 is performed under the hypothesis that one of the pseudoscalars decays to a pair of opposite sign muons and the other decays to bb‾ . Such signatures are predicted in a number of extensions of the standard model (SM), including next-to-minimal supersymmetry and two-Higgs-doublet models with an additional scalar singlet. The results are based on a data set of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb−1 , accumulated with the CMS experiment at the CERN LHC in 2016 at a centre-of-mass energy of 13 TeV. No statistically significant excess is observed with respect to the SM backgrounds in the search region for pseudoscalar masses from 20 GeV to half of the Higgs boson mass. Upper limits at 95% confidence level are set on the product of the production cross section and branching fraction, σhB(h→a1a1→μ+μ−bb‾) , ranging from 5 to 33 fb, depending on the pseudoscalar mass. Corresponding limits on the branching fraction, assuming the SM prediction for σh , are (1–7)×10−4 .Sirunyan, A.M.Wed, 19 Jun 2019 14:15:45 GMThttps://repo.scoap3.org/record/334442019-08-10Search for dark matter in events with a leptoquark and missing transverse momentum in proton-proton collisions at 13 TeV
https://repo.scoap3.org/record/33443
A search is presented for dark matter in proton-proton collisions at a center-of-mass energy of s=13 TeV using events with at least one high transverse momentum ( pT ) muon, at least one high- pT jet, and large missing transverse momentum. The data were collected with the CMS detector at the CERN LHC in 2016 and 2017, and correspond to an integrated luminosity of 77.4 fb −1 . In the examined scenario, a pair of scalar leptoquarks is assumed to be produced. One leptoquark decays to a muon and a jet while the other decays to dark matter and low- pT standard model particles. The signature for signal events would be significant missing transverse momentum from the dark matter in conjunction with a peak at the leptoquark mass in the invariant mass distribution of the highest pT muon and jet. The data are observed to be consistent with the background predicted by the standard model. For the first benchmark scenario considered, dark matter masses up to 500 GeV are excluded for leptoquark masses mLQ≈1400 GeV, and up to 300 GeV for mLQ≈1500 GeV. For the second benchmark scenario, dark matter masses up to 600 GeV are excluded for mLQ≈1400 GeV.Sirunyan, A.M.Wed, 19 Jun 2019 14:15:31 GMThttps://repo.scoap3.org/record/334432019-08-10Observation and study of the decay <math><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>→</mo><mi>ϕ</mi><mi>η</mi><msup><mi>η</mi><mo>′</mo></msup></math>
https://repo.scoap3.org/record/33399
We report the observation and study of the decay J/ψ→ϕηη′ using 1.3×109 J/ψ events collected with the BESIII detector. Its branching fraction, including all possible intermediate states, is measured to be (2.32±0.06±0.16)×10−4. We also report evidence for a structure, denoted as X, in the ϕη′ mass spectrum in the 2.0–2.1 GeV/c2 region. Using two decay modes of the η′ meson (γπ+π− and ηπ+π−), a simultaneous fit to the ϕη′ mass spectra is performed. Assuming the quantum numbers of the X to be JP=1−, its significance is found to be 4.4σ, with a mass and width of (2002.1±27.5±21.4) MeV/c2 and (129±17±9) MeV, respectively, and a product branching fraction B(J/ψ→ηX)×B(X→ϕη′)=(9.8±1.2±1.7)×10−5. Alternatively, assuming JP=1+, the significance is 3.8σ, with a mass and width of (2062.8±13.1±7.2) MeV/c2 and (177±36±35) MeV, respectively, and a product branching fraction B(J/ψ→ηX)×B(X→ϕη′)=(9.6±1.4±2.0)×10−5. The angular distribution of J/ψ→ηX is studied and the two JP assumptions of the X cannot be clearly distinguished due to the limited statistics. In all measurements the first uncertainties are statistical and the second systematic.Ablikim, M.Tue, 18 Jun 2019 20:16:12 GMThttps://repo.scoap3.org/record/33399APS2019-06-18Study of <math><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><mi>γ</mi><mi>ω</mi><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> and Observation of <math><mrow><mi>X</mi><mo>(</mo><mn>3872</mn><mo>)</mo><mo>→</mo><mi>ω</mi><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math>
https://repo.scoap3.org/record/33381
We study the e+e−→γωJ/ψ process using 11.6 fb−1 e+e− annihilation data taken at center-of-mass energies from s=4.008 GeV to 4.600 GeV with the BESIII detector at the BEPCII storage ring. The X(3872) resonance is observed for the first time in the ωJ/ψ system with a significance of more than 5σ. The relative decay ratio of X(3872)→ωJ/ψ and π+π−J/ψ is measured to be R=1.6−0.3+0.4±0.2, where the first uncertainty is statistical and the second systematic (the same hereafter). The s-dependent cross section of e+e−→γX(3872) is also measured and investigated, and it can be described by a single Breit-Wigner resonance, referred to as the Y(4200), with a mass of 4200.6−13.3+7.9±3.0 MeV/c2 and a width of 115−26+38±12 MeV. In addition, to describe the ωJ/ψ mass distribution above 3.9 GeV/c2, we need at least one additional Breit-Wigner resonance, labeled as X(3915), in the fit. The mass and width of the X(3915) are determined. The resonant parameters of the X(3915) agree with those of the Y(3940) in B→KωJ/ψ and of the X(3915) in γγ→ωJ/ψ observed by the Belle and BABAR experiments within errors.Ablikim, M.Tue, 18 Jun 2019 14:03:14 GMThttps://repo.scoap3.org/record/33381APS2019-06-14Search for a low-mass τ − τ + resonance in association with a bottom quark in proton-proton collisions at s $$ \sqrt{s} $$ = 13 TeV
https://repo.scoap3.org/record/33322
A general search is presented for a low-mass τ − τ + resonance produced in association with a bottom quark. The search is based on proton-proton collision data at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 fb −1 . The data are consistent with the standard model expectation. Upper limits at 95% confidence level on the cross section times branching fraction are determined for two signal models: a light pseudoscalar Higgs boson decaying to a pair of τ leptons produced in association with bottom quarks, and a low-mass boson X decaying to a τ -lepton pair that is produced in the decay of a bottom-like quark B such that B → bX. Masses between 25 and 70 GeV are probed for the light pseudoscalar boson with upper limits ranging from 250 to 44 pb. Upper limits from 20 to 0.3 pb are set on B masses between 170 and 450 GeV for X boson masses between 20 and 70 GeV.Sirunyan, A.Fri, 14 Jun 2019 16:08:58 GMThttps://repo.scoap3.org/record/333222019-05-31Study of the decays <math><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>→</mo><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo>+</mo></msup></math> and <math><msubsup><mi>K</mi><mi>L</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo>+</mo></msup></math>
https://repo.scoap3.org/record/33267
Using an e+e− annihilation data sample corresponding to an integrated luminosity of 3.19 fb−1 and collected at a center-of-mass energy s=4.178 GeV with the BESIII detector, we measure the absolute branching fractions B(Ds+→KS0K+)=(1.425±0.038stat.±0.031syst.)% and B(Ds+→KL0K+)=(1.485±0.039stat.±0.046syst.)%. The branching fraction of Ds+→KS0K+ is compatible with the world average and that of Ds+→KL0K+ is measured for the first time. We present the first measurement of the KS0−KL0 asymmetry in the decays Ds+→KS,L0K+, and R(Ds+→KS,L0K+)=B(Ds+→KS0K+)−B(Ds+→KL0K+)B(Ds+→KS0K+)+B(Ds+→KL0K+)=(−2.1±1.9stat.±1.6syst.)%. In addition, we measure the direct CP asymmetries ACP(Ds±→KS0K±)=(0.6±2.8stat.±0.6syst.)% and ACP(Ds±→KL0K±)=(−1.1±2.6stat.±0.6syst.)%.Ablikim, M.Wed, 12 Jun 2019 16:16:31 GMThttps://repo.scoap3.org/record/33267APS2019-06-12Measurements of the Higgs boson width and anomalous <math><mrow><mi>H</mi><mi>V</mi><mi>V</mi></mrow></math> couplings from on-shell and off-shell production in the four-lepton final state
https://repo.scoap3.org/record/33244
Studies of on-shell and off-shell Higgs boson production in the four-lepton final state are presented, using data from the CMS experiment at the LHC that correspond to an integrated luminosity of 80.2 fb−1 at a center-of-mass energy of 13 TeV. Joint constraints are set on the Higgs boson total width and parameters that express its anomalous couplings to two electroweak vector bosons. These results are combined with those obtained from the data collected at center-of-mass energies of 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb−1, respectively. Kinematic information from the decay particles and the associated jets are combined using matrix element techniques to identify the production mechanism and to increase sensitivity to the Higgs boson couplings in both production and decay. The constraints on anomalous HVV couplings are found to be consistent with the standard model expectation in both the on-shell and off-shell regions. Under the assumption of a coupling structure similar to that in the standard model, the Higgs boson width is constrained to be 3.2−2.2+2.8 MeV while the expected constraint based on simulation is 4.1−4.0+5.0 MeV. The constraints on the width remain similar with the inclusion of the tested anomalous HVV interactions.Sirunyan, A. M.Wed, 12 Jun 2019 00:16:29 GMThttps://repo.scoap3.org/record/33244APS2019-06-11Probing dark matter particles at CEPC
https://repo.scoap3.org/record/33222
We investigate the capability of the future electron collider CEPC in probing the parameter space of several dark matter models, including millicharged dark matter models, Z ′ portal dark matter models, and effective dark matter operators. In our analysis, the monophoton final state is used as the primary channel to detect dark matter models at CEPC. To maximize the signal to background significance, we study the energy and angular distributions of the monophoton channel arising from dark matter models and from the standard model to design a set of detector cuts. For the Z ′ portal dark matter, we also analyze the Z ′ boson visible decay channel which is found to be complementary to the monophoton channel in certain parameter space. The CEPC reach in the parameter space of dark matter models is also put in comparison with Xenon1T. We find that CEPC has the unprecedented sensitivity to certain parameter space for the dark matter models considered; for example, CEPC can improve the limits on millicharge by one order of magnitude than previous collider experiments for O 1 − 100 $$ \mathcal{O}(1)-100 $$ GeV dark matter.Liu, ZuoweiTue, 11 Jun 2019 14:06:30 GMThttps://repo.scoap3.org/record/332222019-06-04Search for heavy Majorana neutrino in lepton number violating decays of <math><mi>D</mi><mo>→</mo><mi>K</mi><mi>π</mi><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>+</mo></msup></math>
https://repo.scoap3.org/record/33166
Using a data sample with an integrated luminosity of 2.93 fb−1 taken at the center-of-mass energy of 3.773 GeV, we search for the Majorana neutrino (νm) in the lepton number violating decays D→Kπe+e+. No significant signal is observed, and the upper limits on the branching fraction at the 90% confidence level are set to be B(D0→K−π−e+e+)<2.8×10−6, B(D+→KS0π−e+e+)<3.3×10−6 and B(D+→K−π0e+e+)<8.5×10−6. The Majorana neutrino is searched for with different mass assumptions ranging from 0.25 to 1.0 GeV/c2 in the decays D0→K−e+νm,νm→π−e+ and D+→KS0e+νm,νm→π−e+, and the upper limits on the branching fraction at the 90% confidence level are at the level of 10−7∼10−6, depending on the mass of the Majorana neutrino. The constraints on the mixing matrix element |Veνm|2 are also evaluated.Ablikim, M.Fri, 07 Jun 2019 00:16:25 GMThttps://repo.scoap3.org/record/33166APS2019-06-06FCC Physics Opportunities
https://repo.scoap3.org/record/33144
We review the physics opportunities of the Future Circular Collider, covering its e + e - , pp, ep and heavy ion programmes. We describe the measurement capabilities of each FCC component, addressing the study of electroweak, Higgs and strong interactions, the top quark and flavour, as well as phenomena beyond the Standard Model. We highlight the synergy and complementarity of the different colliders, which will contribute to a uniquely coherent and ambitious research programme, providing an unmatchable combination of precision and sensitivity to new physics.Abada, A.Wed, 05 Jun 2019 13:47:13 GMThttps://repo.scoap3.org/record/331442019-6-5Amplitude analysis and branching fraction measurement of <math><mrow><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>→</mo><msup><mrow><mi>K</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math>
https://repo.scoap3.org/record/33098
Utilizing the dataset corresponding to an integrated luminosity of 2.93 fb−1 at s=3.773 GeV collected by the BESIII detector, we report the first amplitude analysis and branching fraction measurement of the D0→K−π+π0π0 decay. We investigate the substructures and determine the relative fractions and the phases among the different intermediate processes. Our results are used to provide an accurate detection efficiency and allow measurement of B(D0→K−π+π0π0)=(8.86±0.13(stat)±0.19(syst))%.Ablikim, M.Fri, 31 May 2019 16:16:22 GMThttps://repo.scoap3.org/record/33098urn:ISSN:2470-0029APS2019-05-31Observation of the Decay <math><mi>X</mi><mo>(</mo><mn>3872</mn><mo>)</mo><mo>→</mo><msup><mi>π</mi><mn>0</mn></msup><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo>(</mo><mn>1</mn><mi>P</mi><mo>)</mo></math>
https://repo.scoap3.org/record/32994
Using a total of 9.0 fb−1 of e+e− collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e+e−→γX(3872) with X(3872)→π0χcJ for J=0, 1, 2. We report the first observation of X(3872)→π0χc1, a new decay mode of the X(3872), with a statistical significance of more than 5σ for all systematic fit variations. Normalizing to the previously established process e+e−→γX(3872) with X(3872)→π+π−J/ψ, we find B(X(3872)→π0χc1)/B(X(3872)→π+π−J/ψ)=0.88−0.27+0.33±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π0χc0 and π0χc2 of 19 and 1.1, respectively.Ablikim, M.Tue, 28 May 2019 09:41:22 GMThttps://repo.scoap3.org/record/32994urn:ISSN:1079-7114APS2019-05-23Search for associated production of a Higgs boson and a single top quark in proton-proton collisions at <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>
https://repo.scoap3.org/record/32898
A search is presented for the production of a Higgs boson in association with a single top quark, based on data collected in 2016 by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of 35.9 fb−1. The production cross section for this process is highly sensitive to the absolute values of the top quark Yukawa coupling, yt; the Higgs boson coupling to vector bosons, gHVV; and, uniquely, their relative sign. Analyses using multilepton signatures, targeting H→WW, H→ττ, and H→ZZ decay modes, and signatures with a single lepton and a bb¯ pair, targeting the H→bb¯ decay, are combined with a reinterpretation of a measurement in the H→γγ channel to constrain yt. For a standard model–like value of gHVV, the data favor positive values of yt and exclude values of yt below about −0.9ytSM.Sirunyan, A. M.Tue, 28 May 2019 09:36:08 GMThttps://repo.scoap3.org/record/32898urn:ISSN:2470-0029APS2019-05-21Cross section measurements of <math><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo>→</mo><mi>ω</mi><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub></math> from <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>4.178</mn></math> to 4.278 GeV
https://repo.scoap3.org/record/32874
The cross section of the process e+e−→ωχc0 is measured at center-of-mass energies from s=4.178 to 4.278 GeV using a data sample of 7 fb−1 collected with the BESIII detector operating at the BEPCII storage ring. The dependence of the cross section on s shows a resonant structure with mass of (4218.5±1.6(stat)±4.0(syst)) MeV/c2 and width of (28.2±3.9(stat)±1.6(syst)) MeV, respectively. This observation confirms and improves upon the result of a previous study. The angular distribution of the e+e−→ωχc0 process is extracted for the first time.Ablikim, M.Tue, 28 May 2019 09:34:47 GMThttps://repo.scoap3.org/record/32874urn:ISSN:2470-0029APS2019-05-16Heavy-quark spin and flavor symmetry partners of the <math><mi>X</mi><mo>(</mo><mn>3872</mn><mo>)</mo></math> revisited: What can we learn from the one boson exchange model?
https://repo.scoap3.org/record/32870
Heavy-quark symmetry as applied to heavy hadron systems implies that their interactions are independent of their heavy-quark spin (heavy-quark spin symmetry) and heavy flavor contents (heavy flavor symmetry). In the molecular hypothesis the X(3872) resonance is a 1++ D*D¯ bound state. If this is the case, the application of heavy-quark symmetry to a molecular X(3872) suggests the existence of a series of partner states, the most obvious of which is a possible 2++ D*D¯* bound state for which the two-body potential is identical to that of the 1++ D*D¯ system, the reason being that these two heavy hadron-antihadron states have identical light-spin content. As already discussed in the literature, this leads to the prediction of a partner state at 4012 MeV, at least in the absence of other dynamical effects which might affect the location of this molecule. However the prediction of further heavy-quark symmetry partners cannot be made solely on the basis of symmetry and requires additional information. We propose to use the one-boson-exchange model to fill this gap, in which case we will be able to predict or discard the existence of other partner states. Besides the isoscalar 2++ D*D¯* bound state, we correctly reproduce the location and quantum numbers of the isovector hidden-bottom Zb(10610) and Zb(10650) molecular candidates. We also predict the hidden-bottom 1++ B*B¯* and 2++ B*B¯* partners of the X(3872), in agreement with previous theoretical speculations, plus a series of other states. The isoscalar, doubly charmed 1+ DD* and D*D* molecules, and their doubly bottomed counterparts are likely to bind, providing a few instances of explicitly exotic systems.Liu, Ming-ZhuTue, 28 May 2019 09:34:38 GMThttps://repo.scoap3.org/record/32870urn:ISSN:2470-0029APS2019-05-15Observation of the <math><mrow><mi>W</mi></mrow></math>-annihilation decay <math><mrow><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>→</mo><mi>ω</mi><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math> and evidence for <math><mrow><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>→</mo><mi>ω</mi><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup></mrow></math>
https://repo.scoap3.org/record/32857
We report the observation of W-annihilation decay Ds+→ωπ+ and evidence for Ds+→ωK+ in a data sample corresponding to an integrated luminosity of 3.19 fb−1 collected with the BESIII detector at a center-of-mass energy s=4.178 GeV. We obtain the branching fractions B(Ds+→ωπ+)=(1.77±0.32stat±0.13sys)×10−3 with a significance of 6.7σ and B(Ds+→ωK+)=(0.87±0.24stat±0.08sys)×10−3 with a significance of 4.4σ. This measurement provides critical information to determine the nonperturbative W-annihilation amplitudes and shows the potential of searching for CP asymmetry in Ds+→ωK+.Ablikim, M.Tue, 28 May 2019 09:33:37 GMThttps://repo.scoap3.org/record/32857urn:ISSN:2470-0029APS2019-05-13Study of the process <math><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><mi>p</mi><mover><mrow><mi>p</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math> via initial state radiation at BESIII
https://repo.scoap3.org/record/32851
The Born cross section for the process e+e−→pp¯ is measured using the initial state radiation technique with an undetected photon. This analysis is based on datasets corresponding to an integrated luminosity of 7.5 fb−1, collected with the BESIII detector at the BEPCII collider at center of mass energies between 3.773 and 4.600 GeV. The Born cross section for the process e+e−→pp¯ and the proton effective form factor are determined in the pp¯ invariant mass range between 2.0 and 3.8 GeV/c2 divided into 30 intervals. The proton form factor ratio (|GE|/|GM|) is measured in 3 intervals of the pp¯ invariant mass between 2.0 and 3.0 GeV/c2.Ablikim, M.Tue, 28 May 2019 09:32:46 GMThttps://repo.scoap3.org/record/32851urn:ISSN:2470-0029APS2019-05-10