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First Observation of the Radiative Decay <math><msubsup><mi>Λ</mi><mi>b</mi><mn>0</mn></msubsup><mo>→</mo><mi>Λ</mi><mi>γ</mi></math>
https://repo.scoap3.org/record/33845
The radiative decay Λb0→Λγ is observed for the first time using a data sample of proton-proton collisions corresponding to an integrated luminosity of 1.7 fb−1 collected by the LHCb experiment at a center-of-mass energy of 13 TeV. Its branching fraction is measured exploiting the B0→K*0γ decay as a normalization mode and is found to be B(Λb0→Λγ)=(7.1±1.5±0.6±0.7)×10−6, where the quoted uncertainties are statistical, systematic, and systematic from external inputs, respectively. This is the first observation of a radiative decay of a beauty baryon.Aaij, R.Mon, 15 Jul 2019 20:16:06 GMThttps://repo.scoap3.org/record/33845APS2019-07-15Near-threshold D D ¯ $$ \mathrm{D}\overline{\mathrm{D}} $$ spectroscopy and observation of a new charmonium state
https://repo.scoap3.org/record/33757
Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb −1 , collected with the LHCb detector between 2011 and 2018, a new narrow charmonium state, the X(3842) resonance, is observed in the decay modes X 3842 → D 0 D ¯ 0 $$ \mathrm{X}(3842)\to {D}^0{\overline{D}}^0 $$ and X(3842) → D + D − . The mass and the natural width of this state are measured to beAaij, R.Wed, 10 Jul 2019 10:43:47 GMThttps://repo.scoap3.org/record/337572019-07-08Amplitude analysis of the B s 0 → K ∗ 0 K ¯ ∗ 0 $$ {B}_{(s)}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decays and measurement of the branching fraction of the B 0 → K ∗ 0 K ¯ ∗ 0 $$ {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decay
https://repo.scoap3.org/record/33700
The B 0 → K ∗ 0 K ¯ ∗ 0 $$ {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ and B s 0 → K ∗ 0 K ¯ ∗ 0 $$ {B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3 fb −1 . An untagged and timeintegrated amplitude analysis of B ( s ) 0 → ( K + π − )( K − π + ) decays in two-body invariant mass regions of 150 MeV/ c 2 around the K ∗0 mass is performed. A stronger longitudinal polarisation fraction in the B 0 → K ∗ 0 K ¯ ∗ 0 $$ {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decay, f L = 0 . 724 ± 0 . 051 (stat) ± 0 . 016 (syst), is observed as compared to f L = 0 . 240 ± 0 . 031 (stat) ± 0 . 025 (syst) in the B s 0 → K ∗ 0 K ¯ ∗ 0 $$ {B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} $$ decay. The ratio of branching fractions of the two decays is measured and used to determine ℬ B 0 → K ∗ 0 K ¯ ∗ 0 = 8.0 ± 0.9 stat ± 0.4 syst × 10 − 7 $$ \mathrm{\mathcal{B}}\left({B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}\right)=\left(8.0\pm 0.9\left(\mathrm{stat}\right)\pm 0.4\left(\mathrm{syst}\right)\right)\times {10}^{-7} $$ .Aaij, R.Mon, 08 Jul 2019 11:50:11 GMThttps://repo.scoap3.org/record/337002019-07-05Observation 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/33597APS2019-06-27Amplitude analysis of B s 0 → K S 0 K ± π ∓ decays
https://repo.scoap3.org/record/33523
The first untagged decay-time-integrated amplitude analysis of B s 0 → K S 0 K ± π ∓ decays is performed using a sample corresponding to 3.0 fb −1 of pp collision data recorded with the LHCb detector during 2011 and 2012. The data are described with an amplitude model that contains contributions from the intermediate resonances K * (892) 0,+ , K 2 * (1430) 0,+ and K 0 * (1430) 0,+ , and their charge conjugates. Measurements of the branching fractions of the decay modes B s 0 → K * (892) ± K ∓ and B s 0 → K * — 892 0 K 0 — $$ {B}_s^0\to \overset{\left(\hbox{---} \right)}{K^{*}}{(892)}^0\overset{\left(\hbox{---} \right)}{K^0} $$ are in agreement with, and more precise than, previous results. The decays B s 0 → K 0 * (1430) ± K ∓ and B s 0 → K 0 * — 1430 0 K 0 — $$ {B}_s^0\to \overset{\left(\hbox{---} \right)}{K_0^{*}}{(1430)}^0\overset{\left(\hbox{---} \right)}{K^0} $$ are observed for the first time, each with significance over 10 standard deviations.Aaij, R.Mon, 24 Jun 2019 09:44:32 GMThttps://repo.scoap3.org/record/335232019-06-21Observation 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/33381APS2019-06-14Measurement of the Mass Difference Between Neutral Charm-Meson Eigenstates
https://repo.scoap3.org/record/33380
We report a measurement of the mass difference between neutral charm-meson eigenstates using a novel approach that enhances sensitivity to this parameter. We use 2.3×106 D0→KS0π+π− decays reconstructed in proton-proton collisions collected by the LHCb experiment in 2011 and 2012. Allowing for CP violation in mixing and in the interference between mixing and decay, we measure the CP-averaged normalized mass difference xCP=[2.7±1.6(stat)±0.4(syst)]×10−3 and the CP-violating parameter Δx=[−0.53±0.70(stat)±0.22(syst)]×10−3. The results are consistent with CP symmetry. These determinations are the most precise from a single experiment and, combined with current world-average results, yield the first evidence that the masses of the neutral charm-meson eigenstates differ.Aaij, R.Tue, 18 Jun 2019 14:03:09 GMThttps://repo.scoap3.org/record/33380APS2019-06-14Study 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/33267APS2019-06-12Observation of an Excited <math><msubsup><mi>B</mi><mi>c</mi><mo>+</mo></msubsup></math> State
https://repo.scoap3.org/record/33246
Using pp collision data corresponding to an integrated luminosity of 8.5 fb−1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π− invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc*(2S31)+ state reconstructed without the low-energy photon from the Bc*(1S31)+→Bc+γ decay following Bc*(2S31)+→Bc*(1S31)+π+π−. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date.Aaij, R.Wed, 12 Jun 2019 00:18:11 GMThttps://repo.scoap3.org/record/33246APS2019-06-11Search 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/33166APS2019-06-06Observation of a Narrow Pentaquark State, <math><mrow><msub><mrow><mi>P</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>(</mo><mn>4312</mn><msup><mrow><mo>)</mo></mrow><mrow><mo>+</mo></mrow></msup></mrow></math>, and of the Two-Peak Structure of the <math><msub><mi>P</mi><mi>c</mi></msub><mo>(</mo><mn>4450</mn><msup><mo>)</mo><mo>+</mo></msup></math>
https://repo.scoap3.org/record/33152
A narrow pentaquark state, Pc(4312)+, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λb0→J/ψpK− decays, which is an order of magnitude larger than that previously analyzed by the LHCb Collaboration. The Pc(4450)+ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, Pc(4440)+ and Pc(4457)+, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σc+D¯0 and Σc+D¯*0 thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.Aaij, R.Wed, 05 Jun 2019 20:16:33 GMThttps://repo.scoap3.org/record/33152APS2019-06-05Measurement of the relative <math><mrow><msup><mrow><mi>B</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>/</mo><msup><mrow><mi>D</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo>/</mo><msup><mrow><mi>D</mi></mrow><mrow><mrow><mo>*</mo><mo>*</mo></mrow><mn>0</mn></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup><msub><mrow><mover><mrow><mi>ν</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow><mrow><mi>μ</mi></mrow></msub></mrow></math> branching fractions using <math><msup><mi>B</mi><mo>−</mo></msup></math> mesons from <math><mrow><msubsup><mrow><mover><mrow><mi>B</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow><mrow><mi>s</mi><mn>2</mn></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msubsup></mrow></math> decays
https://repo.scoap3.org/record/33101
The decay of the narrow resonance B¯s2*0→B−K+ can be used to determine the B− momentum in partially reconstructed decays without any assumptions on the decay products of the B− meson. This technique is employed for the first time to distinguish contributions from D0, D*0, and higher-mass charmed states (D**0) in semileptonic B− decays by using the missing-mass distribution. The measurement is performed using a data sample corresponding to an integrated luminosity of 3.0 fb−1 collected with the LHCb detector in pp collisions at center-of-mass energies of 7 and 8 TeV. The resulting branching fractions relative to the inclusive B−→D0Xμ−ν¯μ are fD0=B(B−→D0μ−ν¯μ)/B(B−→D0Xμ−ν¯μ)=0.25±0.06,fD**0=B(B−→(D**0→D0X)μ−ν¯μ)/B(B−→D0Xμ−ν¯μ)=0.21±0.07, with fD*0=1−fD0−fD**0 making up the remainder.Aaij, R.Fri, 31 May 2019 16:16:56 GMThttps://repo.scoap3.org/record/33101urn:ISSN:2470-0029APS2019-05-31Amplitude 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 <math><mi>C</mi><mi>P</mi></math> Violation in Charm Decays
https://repo.scoap3.org/record/33069
A search for charge-parity (CP) violation in D0→K−K+ and D0→π−π+ decays is reported, using pp collision data corresponding to an integrated luminosity of 5.9 fb−1 collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the charm meson is inferred from the charge of the pion in D*(2010)+→D0π+ decays or from the charge of the muon in B¯→D0μ−ν¯μX decays. The difference between the CP asymmetries in D0→K−K+ and D0→π−π+ decays is measured to be ΔACP=[−18.2±3.2(stat)±0.9(syst)]×10−4 for π-tagged and ΔACP=[−9±8(stat)±5(syst)]×10−4 for μ-tagged D0 mesons. Combining these with previous LHCb results leads to ΔACP=(−15.4±2.9)×10−4, where the uncertainty includes both statistical and systematic contributions. The measured value differs from zero by more than 5 standard deviations. This is the first observation of CP violation in the decay of charm hadrons.Aaij, R.Wed, 29 May 2019 20:21:40 GMThttps://repo.scoap3.org/record/33069urn:ISSN:1079-7114APS2019-05-29Observation 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:1079-7114APS2019-05-23Observation of <math><mrow><msubsup><mrow><mi>B</mi></mrow><mrow><mo>(</mo><mi>s</mi><mo>)</mo></mrow><mrow><mn>0</mn></mrow></msubsup><mo>→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>p</mi><mover><mrow><mi>p</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math> Decays and Precision Measurements of the <math><mrow><msubsup><mrow><mi>B</mi></mrow><mrow><mo>(</mo><mi>s</mi><mo>)</mo></mrow><mrow><mn>0</mn></mrow></msubsup></mrow></math> Masses
https://repo.scoap3.org/record/32992
The first observation of the decays B(s)0→J/ψpp¯ is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb−1, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B(B0→J/ψpp¯)=[4.51±0.40(stat)±0.44(syst)]×10−7, B(Bs0→J/ψpp¯)=[3.58±0.19(stat)±0.39(syst)]×10−6. For the Bs0 meson, the result is much higher than the expected value of O(10−9). The small available phase space in these decays also allows for the most precise single measurement of both the B0 mass as 5279.74±0.30(stat)±0.10(syst) MeV and the Bs0 mass as 5366.85±0.19(stat)±0.13(syst) MeV.Aaij, R.Tue, 28 May 2019 09:41:15 GMThttps://repo.scoap3.org/record/32992urn:ISSN:1079-7114APS2019-05-17Search for <math><mi>C</mi><mi>P</mi></math> Violation in <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>π</mi><mo>+</mo></msup></math>, <math><msup><mi>D</mi><mo>+</mo></msup><mo>→</mo><msubsup><mi>K</mi><mi>S</mi><mn>0</mn></msubsup><msup><mi>K</mi><mo>+</mo></msup></math>, and <math><msup><mi>D</mi><mo>+</mo></msup><mo>→</mo><mi>ϕ</mi><msup><mi>π</mi><mo>+</mo></msup></math> Decays
https://repo.scoap3.org/record/32991
A search for charge-parity (CP) violation in Cabibbo-suppressed Ds+→KS0π+, D+→KS0K+, and D+→ϕπ+ decays is reported using proton-proton collision data, corresponding to an integrated luminosity of 3.8 fb−1, collected at a center-of-mass energy of 13 TeV with the LHCb detector. High-yield samples of kinematically and topologically similar Cabibbo-favored D(s)+ decays are analyzed to subtract nuisance asymmetries due to production and detection effects, including those induced by CP violation in the neutral kaon system. The results are ACP(Ds+→KS0π+)=(1.3±1.9±0.5)×10−3,ACP(D+→KS0K+)=(−0.09±0.65±0.48)×10−3,ACP(D+→ϕπ+)=(0.05±0.42±0.29)×10−3,where the first uncertainties are statistical and the second systematic. They are the most precise measurements of these quantities to date, and are consistent with CP symmetry. A combination with previous LHCb measurements, based on data collected at 7 and 8 TeV, is also reported.Aaij, R.Tue, 28 May 2019 09:41:07 GMThttps://repo.scoap3.org/record/32991urn:ISSN:1079-7114APS2019-05-17Search for Lepton-Universality Violation in <math><msup><mi>B</mi><mo>+</mo></msup><mo>→</mo><msup><mi>K</mi><mo>+</mo></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math> Decays
https://repo.scoap3.org/record/32989
A measurement of the ratio of branching fractions of the decays B+→K+μ+μ− and B+→K+e+e− is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0 fb−1 recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1<q2<6.0 GeV2/c4 the ratio of branching fractions is measured to be RK=0.846−0.054+0.060−0.014+0.016, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of RK to date and is compatible with the standard model at the level of 2.5 standard deviations.Aaij, R.Tue, 28 May 2019 09:40:59 GMThttps://repo.scoap3.org/record/32989urn:ISSN:1079-7114APS2019-05-13Cross 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:2470-0029APS2019-05-16Observation 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:2470-0029APS2019-05-10Erratum to: Measurement of ϒ production in pp collisions at s $$ \sqrt{\mathrm{s}} $$ = 13 TeV
https://repo.scoap3.org/record/32739
The top plot shown in figure 3 of ref. [1] is the result of 8 TeV.Aaij, R.Mon, 27 May 2019 15:30:59 GMThttps://repo.scoap3.org/record/32739urn:ISSN:1029-8479Springer/SISSA2019-05-15Study of the B 0 → ρ (770)° K * (892) 0 decay with an amplitude analysis of B 0 → ( π + π − )( K + π − ) decays
https://repo.scoap3.org/record/32692
An amplitude analysis of B 0 → ( π + π − )( K + π − ) decays is performed in the two-body invariant mass regions 300 < m ( π + π − ) < 1100 MeV/ c 2 , accounting for the ρ 0 , ω , f 0 (500), f 0 (980) and f 0 (1370) resonances, and 750 < m ( K + π − ) < 1200 MeV/ c 2 , which is dominated by the K * (892) 0 meson. The analysis uses 3 fb −1 of proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. The CP averages and asymmetries are measured for the magnitudes and phase differences of the con- tributing amplitudes. The CP -averaged longitudinal polarisation fractions of the vector-vector modes are found to be f ˜ ρ K * 0 $$ {\tilde{f}}_{\rho {K}^{*}}^0 $$ = 0 . 164 ± 0 . 015 ± 0 . 022 and f ˜ ω K * 0 $$ {\tilde{f}}_{\omega {K}^{*}}^0 $$ = 0 . 68 ± 0 . 17 ± 0 . 16, and their CP asymmetries, A ρ K * 0 $$ {\mathcal{A}}_{\rho {K}^{*}}^0 $$ = −0 . 62 ± 0 . 09 ± 0 . 09 and A ω K * 0 $$ {\mathcal{A}}_{\omega {K}^{*}}^0 $$ = −0 . 13 ± 0 . 27 ± 0 . 13, where the first uncertainty is statistical and the second systematic.Aaij, R.Mon, 27 May 2019 15:22:58 GMThttps://repo.scoap3.org/record/32692urn:ISSN:1029-8479Springer/SISSA2019-05-06First 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:2470-0029APS2019-04-24