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Measurement of two-particle correlations with respect to second- and third-order event planes in Au + Au collisions at <math><mrow><msqrt><msub><mi>s</mi><mi>NN</mi></msub></msqrt><mo>=</mo><mn>200</mn></mrow></math> GeV
https://repo.scoap3.org/record/32638
We present measurements of azimuthal correlations of charged hadron pairs in sNN=200 GeV Au+Au collisions for the trigger and associated particle transverse-momentum ranges of 1<pTt<10GeV/c and 0.5<pTa<10GeV/c. After subtraction of an underlying event using a model that includes higher-order azimuthal anisotropy v2, v3, and v4, the away-side yield of the highest trigger-pT(pTt>4GeV/c) correlations is suppressed compared with that of correlations measured in p+p collisions. At the lowest associated particle pT(0.5<pTa<1GeV/c), the away-side shape and yield are modified relative to those in p+p collisions. These observations are consistent with the scenario of radiative-jet energy loss. For the low-pT trigger correlations (2<pTt<4GeV/c), a finite away-side yield exists and we explore the dependence of the shape of the away-side within the context of an underlying-event model. Correlations are also studied differentially versus event-plane angle Ψ2 and Ψ3. The angular correlations show an asymmetry when selecting the sign of the difference between the trigger-particle azimuthal angle and the Ψ2 event plane. This asymmetry and the measured suppression of the pair yield out-of-plane is consistent with a path-length-dependent energy loss. No Ψ3 dependence can be resolved within experimental uncertainties.Adare, A.Tue, 07 May 2019 20:16:59 GMThttps://repo.scoap3.org/record/32638urn:ISSN:2469-9993APS2019-05-07Gravitational resonances in mimetic thick branes
https://repo.scoap3.org/record/32527
In this work, we investigate gravitational resonances in both single and double mimetic thick branes, which can provide a new way to detect the extra dimension. For the single brane model, we apply the relative probability proposed in [ Phys. Rev. D 80 (2009) 065019]. For the double brane model, we investigate the resonances quasi-localized on the double brane, on the sub-branes and between the sub-branes, respectively. To investigate the resonances quasi-localized on the double brane, we introduce two different definitions of the relative probability and find that the corresponding mass spectra of gravitational resonances are almost the same. For the gravitational resonances quasi-localized on sub-branes and between the sub-branes, the influence of the distance between the two sub-branes and the thickness of the sub-branes are analyzed and new features are found in both cases.Zhong, YiThu, 02 May 2019 14:59:33 GMThttps://repo.scoap3.org/record/32527urn:ISSN:1029-8479Springer/SISSA2019-04-29Thermodynamics of <math><mrow><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math> flavor Polyakov-loop quark-meson model under external magnetic field
https://repo.scoap3.org/record/32497
We study the thermodynamics of the QCD system under external magnetic field via the 2+1 flavor Polyakov-loop quark-meson model. To incorporate quantum and thermal fluctuations, the functional renormalization group approach is implemented in our work. Pressure, entropy density, magnetic susceptibility, and other thermodynamic quantities are calculated and analyzed to investigate the effect of magnetic field on the QCD system. The calculated results are in reasonable agreement with lattice QCD simulations and perturbation theory. We then give an intuitive picture for the response of the QCD system to the magnetic field.Li, XiangThu, 02 May 2019 14:09:48 GMThttps://repo.scoap3.org/record/32497urn:ISSN:2470-0029APS2019-04-30First observations of <math><mrow><msub><mrow><mi>h</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>→</mo><mtext>hadrons</mtext></mrow></math>
https://repo.scoap3.org/record/32456
Based on (4.48±0.03)×108 ψ(3686) events, collected with the BESIII detector at the BEPCII storage ring, five hc hadronic decays are searched for via the process ψ(3686)→π0hc. Three of them, hc→pp¯π+π−, π+π−π0, and 2(π+π−)π0, are observed for the first time with significances of 7.4σ, 4.6σ, and 9.1σ, and their branching fractions are determined to be (2.89±0.32±0.55)×10−3, (1.60±0.40±0.32)×10−3, and (7.44±0.94±1.52)×10−3, respectively, where the first uncertainties are statistical and the second systematic. No significant signal is observed for the other two decay modes, and the corresponding upper limits of the branching fractions are determined to be B(hc→3(π+π−)π0)<8.7×10−3 and B(hc→K+K−π+π−)<5.8×10−4 at the 90% confidence level.Ablikim, M.Wed, 24 Apr 2019 20:16:35 GMThttps://repo.scoap3.org/record/32456urn:ISSN:2470-0029APS2019-04-24Semi-analytical calculation of gluon fragmentation into 1 S 0 [1,8] quarkonia at next-to-leading order
https://repo.scoap3.org/record/32436
We calculate the NLO corrections for the gluon fragmentation functions to a heavy quark-antiquark pair in 1 S 0 [1] or 1 S 0 [8] state within NRQCD factorization. We use integration-by-parts reduction to reduce the original expression to simpler master integrals (MIs), and then set up differential equations for these MIs. After calculating the boundary conditions, MIs can be obtained by solving the differential equations numerically. Our results are expressed in terms of asymptotic expansions at singular points of z (light-cone momentum fraction carried by the quark-antiquark pair), which can not only give FFs results with very high precision at any value of z , but also provide fully analytical structure at these singularities. We find that the NLO corrections are significant, with K-factors larger than 2 in most regions. The NLO corrections may have important impact on heavy quarkonia (e.g. η c and J/ψ ) production at the LHC.Zhang, PengWed, 24 Apr 2019 18:55:13 GMThttps://repo.scoap3.org/record/32436urn:ISSN:1029-8479Springer/SISSA2019-04-17Nonperturbative-transverse-momentum broadening in dihadron angular correlations in <math><mrow><msqrt><msub><mi>s</mi><msub><mrow></mrow><mrow><mi>N</mi><mi>N</mi></mrow></msub></msub></msqrt><mo>=</mo><mn>200</mn><mspace width="0.16em"></mspace><mi>GeV</mi></mrow></math> proton-nucleus collisions
https://repo.scoap3.org/record/32374
The PHENIX collaboration has measured high-pT dihadron correlations in p+p, p+Al, and p+Au collisions at sNN=200 GeV. The correlations arise from inter- and intrajet correlations and thus have sensitivity to nonperturbative effects in both the initial and final states. The distributions of pout, the transverse-momentum component of the associated hadron perpendicular to the trigger hadron, are sensitive to initial- and final-state transverse momenta. These distributions are measured multidifferentially as a function of xE, the longitudinal momentum fraction of the associated hadron with respect to the trigger hadron. The near-side pout widths, sensitive to fragmentation transverse momentum, show no significant broadening between p+Au, p+Al, and p+p. The away-side nonperturbative pout widths are found to be broadened in p+Au when compared to p+p; however, there is no significant broadening in p+Al compared to p+p collisions. The data also suggest that the away-side pout broadening is a function of Ncoll, the number of binary nucleon-nucleon collisions, in the interaction. The potential implications of these results with regard to initial- and final-state transverse-momentum broadening and energy loss of partons in a nucleus, among other nuclear effects, are discussed.Aidala, C.Thu, 18 Apr 2019 16:16:42 GMThttps://repo.scoap3.org/record/32374urn:ISSN:2469-9993APS2019-04-18Model-Independent Observation of Exotic Contributions to <math><msup><mi>B</mi><mn>0</mn></msup><mo>→</mo><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><msup><mi>K</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> Decays
https://repo.scoap3.org/record/32365
An angular analysis of B0→J/ψK+π− decays is performed, using proton-proton collision data corresponding to an integrated luminosity of 3 fb−1 collected with the LHCb detector. The m(K+π−) spectrum is divided into fine bins. In each m(K+π−) bin, the hypothesis that the three-dimensional angular distribution can be described by structures induced only by K* resonances is examined, making minimal assumptions about the K+π− system. The data reject the K*-only hypothesis with a large significance, implying the observation of exotic contributions in a model-independent fashion. Inspection of the m(J/ψπ−) vs m(K+π−) plane suggests structures near m(J/ψπ−)=4200 and 4600 MeV.Aaij, R.Thu, 18 Apr 2019 04:16:44 GMThttps://repo.scoap3.org/record/32365urn:ISSN:1079-7114APS2019-04-17Observation of the doubly Cabibbo-suppressed decay Ξ c + → pϕ
https://repo.scoap3.org/record/32281
The doubly Cabibbo-suppressed decay Ξ c + → pϕ with ϕ → K + K − is observed for the first time, with a statistical significance of more than fifteen standard deviations. The data sample used in this analysis corresponds to an integrated luminosity of 2 fb −1 recorded with the LHCb detector in pp collisions at a centre-of-mass energy of 8 TeV. The ratio of branching fractions between the decay Ξ c + → pϕ and the singly Cabibbo-suppressed decay Ξ c + → pK − π + is measured to be ℬ Ξ c + → p ϕ ℬ Ξ c + → p K − π + = 19.8 ± 0.7 ± 0.9 ± 0.2 × 10 − 3 , $$ \frac{\mathrm{\mathcal{B}}\left({\varXi}_c^{+}\to p\phi \right)}{\mathrm{\mathcal{B}}\left({\varXi}_c^{+}\to p{K}^{-}{\pi}^{+}\right)}=\left(19.8\pm 0.7\pm 0.9\pm 0.2\right)\times {10}^{-3}, $$Aaij, R.Sat, 13 Apr 2019 16:01:19 GMThttps://repo.scoap3.org/record/32281urn:ISSN:1029-8479Springer/SISSA2019-04-10Constraints on generalized Eddington-inspired Born-Infeld branes
https://repo.scoap3.org/record/32271
The Palatini f(|Ω^|) gravity is a generalized theory of the Eddington-inspired Born-Infeld gravity, where ΩKN≡δKN+bgKLRLN(Γ) is an auxiliary tensor constructed with the spacetime metric g and independent connection Γ. In this paper, we study f(|Ω^|) theory with f(|Ω^|)=|Ω^|12+n in the thick brane scenario and give some constraints on the brane model. We finally found an analytic solution of the thick brane generated by a single scalar field. The behavior of the negative energy density denotes the localization of the thick brane at the origin of the extra dimension. In our braneworld, the warp factor is divergent at the boundary of the extra dimension while the brane system is asymptotically anti–de Sitter. It is shown that the tensor perturbation of the brane is stable and the massless graviton is localized on the thick brane. Therefore, the effective Einstein-Hilbert action on the brane can be rebuilt in the low-energy approximation. According to the recent test of the gravitational inverse-square law, we give some constraints on the f(|Ω^|) brane.Lin, Zi-ChaoSat, 13 Apr 2019 00:17:25 GMThttps://repo.scoap3.org/record/32271urn:ISSN:2470-0029APS2019-04-12Search for baryon and lepton number violation in <math><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>→</mo><msubsup><mrow><mi>Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>+</mo><mi>c</mi><mo>.</mo><mi>c</mi><mo>.</mo></mrow></math>
https://repo.scoap3.org/record/32270
Using 1.31×109 J/ψ events collected by the BESIII detector at the Beijing Electron Positron Collider, we search for the process J/ψ→Λc+e−+c.c. for the first time. In this process, both baryon and lepton number conservation is violated. No signal is found and the upper limit on the branching fraction B(J/ψ→Λc+e−+c.c.) is set to be 6.9×10−8 at the 90% confidence level.Ablikim, M.Sat, 13 Apr 2019 00:17:05 GMThttps://repo.scoap3.org/record/32270urn:ISSN:2470-0029APS2019-04-12Dalitz plot analysis of the D + → K − K + K + decay
https://repo.scoap3.org/record/32245
The resonant structure of the doubly Cabibbo-suppressed decay D + → K − K + K + is studied for the first time. The measurement is based on a sample of pp -collision data, collected at a centre-of-mass energy of 8 TeV with the LHCb detector and corresponding to an integrated luminosity of 2 fb −1 . The amplitude analysis of this decay is performed with the isobar model and a phenomenological model based on an effective chiral Lagrangian. In both models the S-wave component in the K − K + system is dominant, with a small contribution of the ϕ (1020) meson and a negligible contribution from tensor resonances. The K + K − scattering amplitudes for the considered combinations of spin (0,1) and isospin (0,1) of the two-body system are obtained from the Dalitz plot fit with the phenomenological decay amplitude.Aaij, R.Fri, 12 Apr 2019 14:27:01 GMThttps://repo.scoap3.org/record/32245urn:ISSN:1029-8479Springer/SISSA2019-04-08Determining arbitrary Feynman integrals by vacuum integrals
https://repo.scoap3.org/record/32237
By introducing an auxiliary parameter, we find a new representation for Feynman integrals, which defines a Feynman integral by analytical continuation of a series containing only vacuum integrals. The new representation therefore conceptually translates the problem of computing Feynman integrals to the problem of performing analytical continuations. As an application of the new representation, we use it to construct a novel reduction method for multiloop Feynman integrals, which is expected to be more efficient than the known integration-by-parts reduction method. Using the new method, we successfully reduced all complicated two-loop integrals in the gg→HH process and gg→ggg process.Liu, XiaoFri, 12 Apr 2019 00:17:14 GMThttps://repo.scoap3.org/record/32237urn:ISSN:2470-0029APS2019-04-11Precision measurements of the <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><msubsup><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow><mrow><mn>0</mn></mrow></msubsup><msup><mrow><mi>K</mi></mrow><mrow><mo>±</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>∓</mo></mrow></msup></mrow></math> Born cross sections at center-of-mass energies between 3.8 and 4.6 GeV
https://repo.scoap3.org/record/32236
Using data samples collected by the BESIII detector operating at the BEPCII storage ring, we measure the e+e−→KS0K±π∓ Born cross sections at center-of-mass energies between 3.8 and 4.6 GeV, corresponding to a luminosity of about 5.0 fb−1. The results are compatible with the BABAR measurements, but with the precision significantly improved. A simple 1/sn dependence for the continuum process can describe the measured cross sections, but a better fit is obtained by an additional resonance near 4.2 GeV, which could be an excited charmonium or a charmoniumlike state.Ablikim, M.Fri, 12 Apr 2019 00:16:50 GMThttps://repo.scoap3.org/record/32236urn:ISSN:2470-0029APS2019-04-11Soft drop groomed jet angularities at the LHC
https://repo.scoap3.org/record/32231
Jet angularities are a class of jet substructure observables where a continuous parameter is introduced in order to interpolate between different classic observables such as the jet mass and jet broadening. We consider jet angularities measured on an inclusive jet sample at the LHC where the soft drop grooming procedure is applied in order to remove soft contaminations from the jets. The soft drop algorithm allows for a precise comparison between theory and data and could be used to extract the QCD strong coupling constant αs from jet substructure data in the future. We develop a framework to realize the resummation of all relevant large logarithms at the next-to-leading logarithmic (NLL) accuracy. To demonstrate that the developed formalism is suitable for the extraction of αs , we extend our calculations to next-to-next-to-leading logarithm (NNLL) for the jet mass case. Overall, we find good agreement between our NLL numerical results and Pythia simulations for LHC kinematics and we observe an improved agreement when the NNLL components are included. In addition, we expect that groomed jet angularities will be a useful handle for studying the modification of jets in heavy-ion collisions.Kang, Zhong-BoThu, 11 Apr 2019 17:19:42 GMThttps://repo.scoap3.org/record/32231urn:ISSN:0370-2693Elsevier2019-05-20Measurements of <math><mi>μ</mi><mi>μ</mi></math> pairs from open heavy flavor and Drell-Yan in <math><mi>p</mi><mo>+</mo><mi>p</mi></math> collisions at <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>200</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>
https://repo.scoap3.org/record/32201
PHENIX reports differential cross sections of μμ pairs from semileptonic heavy-flavor decays and the Drell-Yan production mechanism measured in p+p collisions at s=200 GeV at forward and backward rapidity (1.2<|η|<2.2). The μμ pairs from cc¯, bb¯, and Drell-Yan are separated using a template fit to unlike- and like-sign muon pair spectra in mass and pT. The azimuthal opening angle correlation between the muons from cc¯ and bb¯ decays and the pair-pT distributions are compared to distributions generated using pythia and powheg models, which both include next-to-leading order processes. The measured distributions for pairs from cc¯ are consistent with pythia calculations. The cc¯ data present narrower azimuthal correlations and softer pT distributions compared to distributions generated from powheg. The bb¯ data are well described by both models. The extrapolated total cross section for bottom production is 3.75±0.24(stat)±0.500.35(syst)±0.45(global) [μb], which is consistent with previous measurements at the Relativistic Heavy Ion Collider in the same system at the same collision energy and is approximately a factor of 2 higher than the central value calculated with theoretical models. The measured Drell-Yan cross section is in good agreement with next-to-leading-order quantum-chromodynamics calculations.Aidala, C.Wed, 10 Apr 2019 20:16:11 GMThttps://repo.scoap3.org/record/32201urn:ISSN:2470-0029APS2019-04-10Precision Measurement of the Branching Fractions of <math><mrow><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></math> Decays
https://repo.scoap3.org/record/32182
Based on a sample of (1310.6±7.0)×106J/ψ events collected with the BESIII detector, we present measurements of J/ψ and η′ absolute branching fractions using the process J/ψ→γη′. By analyzing events where the radiative photon converts into an e+e− pair, the branching fraction for J/ψ→γη′ is measured to be (5.27±0.03±0.05)×10−3. The absolute branching fractions of the five dominant decay channels of the η′ are then measured for the first time and are determined to be B(η′→γπ+π−)=(29.90±0.03±0.55)%, B(η′→ηπ+π−)=(41.24±0.08±1.24)%, B(η′→ηπ0π0)=(21.36±0.10±0.92)%, B(η′→γω)=(2.489±0.018±0.074)%, and B(η′→γγ)=(2.331±0.012±0.035)%, where the first uncertainties are statistical and the second systematic.Ablikim, M.Wed, 10 Apr 2019 00:17:31 GMThttps://repo.scoap3.org/record/32182urn:ISSN:1079-7114APS2019-04-09Search for the decay <math><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo>→</mo><mi>γ</mi><msup><mi>e</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>e</mi></msub></math>
https://repo.scoap3.org/record/32180
A search for the rare radiative leptonic decay Ds+→γe+νe is performed for the first time using electron-positron collision data corresponding to an integrated luminosity of 3.19 fb−1, collected with the BESIII detector at a center-of-mass energy of 4.178 GeV. No evidence for the Ds+→γe+νe decay is seen, and an upper limit of B(Ds+→γe+νe)<1.3×10−4 is set on the partial branching fraction at a 90% confidence level for radiative photon energies Eγ*>0.01 GeV.Ablikim, M.Wed, 10 Apr 2019 00:16:27 GMThttps://repo.scoap3.org/record/32180urn:ISSN:2470-0029APS2019-04-09First Measurement of Charm Production in its Fixed-Target Configuration at the LHC
https://repo.scoap3.org/record/32041
The first measurement of heavy-flavor production by the LHCb experiment in its fixed-target mode is presented. The production of J/ψ and D0 mesons is studied with beams of protons of different energies colliding with gaseous targets of helium and argon with nucleon-nucleon center-of-mass energies of sNN=86.6 and 110.4 GeV, respectively. The J/ψ and D0 production cross sections in pHe collisions in the rapidity range [2, 4.6] are found to be σJ/ψ=652±33(stat)±42(syst) nb/nucleon and σD0=80.8±2.4(stat)±6.3(syst) μb/nucleon, where the first uncertainty is statistical and the second is systematic. No evidence for a substantial intrinsic charm content of the nucleon is observed in the large Bjorken-x region.Aaij, R.Tue, 09 Apr 2019 15:06:37 GMThttps://repo.scoap3.org/record/32041urn:ISSN:1079-7114APS2019-04-02Measurement of the branching fraction of <math><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>→</mo><mi>ω</mi><msup><mi>η</mi><mo>′</mo></msup><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> and search for <math><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>→</mo><mi>ω</mi><mi>X</mi><mo>(</mo><mn>1835</mn><mo>)</mo></math>, <math><mi>X</mi><mo>(</mo><mn>1835</mn><mo>)</mo><mo>→</mo><msup><mi>η</mi><mo>′</mo></msup><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> decay
https://repo.scoap3.org/record/32008
Using a sample of 1.31×109 J/ψ events collected by the BESIII detector at BEPCII during 2009 and 2012, we study the J/ψ→ωη′π+π− hadronic process. For the first time, we measure the branching ratio B(J/ψ→ωη′π+π−)=(1.12±0.02±0.13)×10−3. We search for the X(1835) state in the η′π+π− invariant mass spectra. No evidence is found and we estimate the upper limit on the branching fraction at 90% confidence level to be B(J/ψ→ωX(1835),X(1835)→η′π+π−)<6.2×10−5.Ablikim, M.Tue, 09 Apr 2019 15:04:54 GMThttps://repo.scoap3.org/record/32008urn:ISSN:2470-0029APS2019-04-05Study of unflavored light mesons with <math><msup><mi>J</mi><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><msup><mn>2</mn><mrow><mo>−</mo><mo>−</mo></mrow></msup></math>
https://repo.scoap3.org/record/31990
The unflavored light meson families, namely, ω2, ρ2, and ϕ2, are studied systematically by investigating the spectrum and the two-body strong decays allowed by the Okubo-Zweig-Iizuka rule. Including the four experimentally observed states and other predicted states, phenomenological analysis of the partial decay widths can verify the corresponding assignments of these states into the families. Moreover, we provide typical branching ratios of the dominant decay channels, especially for missing ground states, which is helpful to search for or confirm them and explore more properties of these families in experiments.Guo, DanTue, 09 Apr 2019 15:03:20 GMThttps://repo.scoap3.org/record/31990urn:ISSN:2470-0029APS2019-03-06Measurement of the longitudinal spin asymmetries for weak boson production in proton-proton collisions at <math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>510</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>
https://repo.scoap3.org/record/31987
We report new STAR measurements of the single-spin asymmetries AL for W+ and W− bosons produced in polarized proton-proton collisions at s=510 GeV as a function of the decay-positron and decay-electron pseudorapidity. The data were obtained in 2013 and correspond to an integrated luminosity of 250 pb−1. The results are combined with previous results obtained with 86 pb−1. A comparison with theoretical expectations based on polarized lepton-nucleon deep-inelastic scattering and prior polarized proton-proton data suggests a difference between the u¯ and d¯ quark helicity distributions for 0.05<x<0.25. In addition, we report new results for the double-spin asymmetries ALL for W±, as well as AL for Z/γ* production and subsequent decay into electron-positron pairs.Adam, J.Tue, 09 Apr 2019 15:03:10 GMThttps://repo.scoap3.org/record/31987urn:ISSN:2470-0029APS2019-03-14Measurement of <math><msup><mi>B</mi><mo>+</mo></msup></math>, <math><msup><mi>B</mi><mn>0</mn></msup></math> and <math><msubsup><mi>Λ</mi><mi>b</mi><mn>0</mn></msubsup></math> production in <math><mrow><mi>p</mi><mi>Pb</mi></mrow></math> collisions at <math><msqrt><msub><mi>s</mi><mrow><mi>NN</mi></mrow></msub></msqrt><mo>=</mo><mn>8.16</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>
https://repo.scoap3.org/record/31887
The production of B+, B0 and Λb0 hadrons is studied in proton-lead collisions at a center-of-mass energy per nucleon pair of sNN=8.16 TeV recorded with the LHCb detector at the LHC. The measurement uses a dataset corresponding to an integrated luminosity of 12.2±0.3 nb−1 for the case where the proton beam is projected into the LHCb detector (corresponding to measuring hadron production at positive rapidity) and 18.6±0.5 nb−1 for the lead beam projected into the LHCb detector (corresponding to measuring hadron production at negative rapidity). Double-differential cross sections are measured and used to determine forward-backward ratios and nuclear modification factors, which directly probe nuclear effects in the production of beauty hadrons. The double-differential cross sections are measured as a function of the beauty-hadron transverse momentum and rapidity in the nucleon-nucleon center-of-mass frame. Forward-to-backward cross section ratios and nuclear modification factors indicate a significant nuclear suppression at positive rapidity. The ratio of Λb0 over B0 production cross sections is reported and is consistent with the corresponding measurement in pp collisions.Aaij, R.Wed, 27 Mar 2019 21:17:25 GMThttps://repo.scoap3.org/record/31887urn:ISSN:2470-0029APS2019-03-27Search for rare decay <math><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>→</mo><mi>ϕ</mi><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math>
https://repo.scoap3.org/record/31834
Using a data sample of 448.1×106 ψ(3686) events collected at s=3.686 GeV with the BESIII detector at the Beijing Electron-Positron Collider II, we search for the rare decay J/ψ→ϕe+e− via ψ(3686)→π+π−J/ψ. No signal events are observed and the upper limit on the branching fraction is set to be B(J/ψ→ϕe+e−)<1.2×10−7 at the 90% confidence level, which is still about one order of magnitude higher than the Standard Model prediction.Ablikim, M.Tue, 26 Mar 2019 17:16:48 GMThttps://repo.scoap3.org/record/31834urn:ISSN:2470-0029APS2019-03-26Measurement of the Dynamics of the Decays <math><mrow><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo>→</mo><msup><mrow><mi>η</mi></mrow><mrow><mo>(</mo><mo>′</mo><mo>)</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub></mrow></math>
https://repo.scoap3.org/record/31818
Using e+e− annihilation data corresponding to an integrated luminosity of 3.19 fb−1 collected at a center-of-mass energy of 4.178 GeV with the BESIII detector, we measure the absolute branching fractions BDs+→ηe+νe=(2.323±0.063stat±0.063syst)% and BDs+→η′e+νe=(0.824±0.073stat±0.027syst)% via a tagged analysis technique, where one Ds is fully reconstructed in a hadronic mode. Combining these measurements with previous BESIII measurements of BD+→η(′)e+νe, the η−η′ mixing angle in the quark flavor basis is determined to be ϕP=(40.1±2.1stat±0.7syst)°. From the first measurements of the dynamics of Ds+→η(′)e+νe decays, the products of the hadronic form factors f+η(′)(0) and the Cabibbo-Kobayashi-Maskawa matrix element |Vcs| are determined with different form factor parametrizations. For the two-parameter series expansion, the results are f+η(0)|Vcs|=0.4455±0.0053stat±0.0044syst and f+η′(0)|Vcs|=0.477±0.049stat±0.011syst.Ablikim, M.Tue, 26 Mar 2019 01:16:16 GMThttps://repo.scoap3.org/record/31818urn:ISSN:1079-7114APS2019-03-25Measurement of the ratio of branching fractions of the decays Λ b 0 → ψ (2 S )Λ and Λ b 0 → J / ψ Λ
https://repo.scoap3.org/record/31810
Using pp collisions corresponding to 3 fb −1 integrated luminosity, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, the ratio of branching fractions ℬ Λ b 0 → ψ 2 S Λ / ℬ Λ b 0 → J / ψ Λ = 0.513 ± 0.023 stat ± 0.016 syst ± 0.011 ℬ $$ \mathrm{\mathcal{B}}\left({\Lambda}_b^0\to \psi (2S)\Lambda \right)/\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to J/\psi \Lambda \right)=0.513\pm 0.023\left(\mathrm{stat}\right)\pm 0.016\left(\mathrm{syst}\right)\pm 0.011\left(\mathrm{\mathcal{B}}\right) $$ is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.Aaij, R.Mon, 25 Mar 2019 20:20:58 GMThttps://repo.scoap3.org/record/31810urn:ISSN:1029-8479Springer/SISSA2019-03-22