A
bstract
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
$$ \mathrm{X}(3842)\to {D}^0{\overline{D}}^0 $$
X
3842
→
D
0
D
¯
0
and X(3842) →
D
+
D
−
. The mass and the natural width of this state are measured to be
$$ \begin{array}{l}{m}_{X(3842)}=3842.71\pm 0.16\pm 0.12\ MeV/{c}^2,\hfill \\ {}{\varGamma}_{X(3842)}=2.79\pm 0.51\pm 0.35\ MeV,\hfill \end{array} $$
m
X
3842
=
3842.71
±
0.16
±
0.12
M
e
V
/
c
2
,
Γ
X
3842
=
2.79
±
0.51
±
0.35
M
e
V
,
where the first uncertainty is statistical and the second is systematic. The observed mass and narrow natural width suggest the interpretation of the new state as the unobserved (spin-3
ψ
3
1
3
D
3
) charmonium state.
In addition, prompt hadroproduction of the
ψ
(3770) and
χ
2
(3930) states is observed for the first time, and the parameters of these states are measured to be
$$ \begin{array}{l}{m}_{\psi (3770)}=3778.1\pm 0.7\pm 0.6\ MeV/{c}^2,\hfill \\ {}{m}_{\chi_2(3930)}=3921.9\pm 0.6\pm 0.2\ MeV/{c}^2,\hfill \\ {}{\varGamma}_{\chi_2(3930)}=36.6 \pm 1.9 \pm 0.9\ MeV,\hfill \end{array} $$
m
ψ
3770
=
3778.1
±
0.7
±
0.6
M
e
V
/
c
2
,
m
χ
2
3930
=
3921.9
±
0.6
±
0.2
M
e
V
/
c
2
,
Γ
χ
2
3930
=
36.6
±
1.9
±
0.9
M
e
V
,
where the first uncertainty is statistical and the second is systematic.
Abstract A first search for $$CP$$ CP violation in the Cabibbo-suppressed $${{{\varXi }} ^+_{c}} \rightarrow {p} {{K} ^-} {{\pi } ^+} $$ Ξ c + → p K - π + decay is performed using both a binned and ...an unbinned model-independent technique in the Dalitz plot. The studies are based on a sample of proton-proton collision data, corresponding to an integrated luminosity of $$3.0\,\text {fb} ^{-1} $$ 3.0 fb - 1 , and collected by the LHCb experiment at centre-of-mass energies of 7 and $$8\,\text {TeV} $$ 8 TeV . The data are consistent with the hypothesis of no $$CP$$ CP violation.
Decays of Bs0 and B‾0s mesons into J/ψπ+π− final states are studied in a data sample corresponding to 1.9 fb−1 of integrated luminosity collected with the LHCb detector in 13 TeV pp collisions. A ...time-dependent amplitude analysis is used to determine the final-state resonance contributions, the CP-violating phase ϕs=−0.057±0.060±0.011 rad, the decay-width difference between the heavier mass Bs0 eigenstate and the B0 meson of −0.050±0.004±0.004 ps−1, and the CP-violating parameter |λ|=1.01−0.06+0.08±0.03, where the first uncertainty is statistical and the second systematic. These results are combined with previous LHCb measurements in the same decay channel using 7 TeV and 8 TeV pp collisions obtaining ϕs=0.002±0.044±0.012 rad, and |λ|=0.949±0.036±0.019.
Abstract Using a data sample corresponding to an integrated luminosity of 2.0 $$\, \text {fb} ^{-1}$$ fb-1 , collected by the LHCb experiment, the production of the $${\eta _{c}} (1S)$$ ηc(1S) state ...in proton–proton collisions at a centre-of-mass energy of $$\sqrt{s} =13$$ s=13 $$\, \text {TeV}$$ TeV is studied in the rapidity range $$2.0< y < 4.5$$ 2.0<y<4.5 and in the transverse momentum range $$6.5< p_{\mathrm {T}} < 14.0 \, \text {GeV} $$ 6.5<pT<14.0GeV . The cross-section for prompt production of $${\eta _{c}} (1S)$$ ηc(1S) mesons relative to that of the $${J /\psi }$$ J/ψ meson is measured using the $$p $$ p $$\overline{{p}}$$ p¯ decay mode and is found to be $${\sigma _{{\eta _{c}} (1S)}/\sigma _{{{J /\psi }}} = 1.69 \pm 0.15 \pm 0.10 \pm 0.18}$$ σηc(1S)/σJ/ψ=1.69±0.15±0.10±0.18 . The quoted uncertainties are, in order, statistical, systematic and due to uncertainties on the branching fractions of the $${{J /\psi }} \!\rightarrow {p} {\overline{{p}}} $$ J/ψ→pp¯ and $${\eta _{c}} \!\rightarrow {p} {\overline{{p}}} $$ ηc→pp¯ decays. The prompt $${\eta _{c}} (1S)$$ ηc(1S) production cross-section is determined to be $${\sigma _{{\eta _{c}} (1S)} = 1.26 \pm 0.11\pm 0.08\pm 0.14 \,\upmu \text {b}}$$ σηc(1S)=1.26±0.11±0.08±0.14μb , where the last uncertainty includes that on the $${J /\psi }$$ J/ψ meson cross-section. The ratio of the branching fractions of $$b $$ b -hadron decays to the $${\eta _{c}} (1S)$$ ηc(1S) and $${J /\psi }$$ J/ψ states is measured to be $${{\mathcal {B}} _{{b} \!\rightarrow {\eta _{c}} X}/{\mathcal {B}} _{{b} \!\rightarrow {{J /\psi }} X} = 0.48 \pm 0.03 \pm 0.03 \pm 0.05}$$ Bb→ηcX/Bb→J/ψX=0.48±0.03±0.03±0.05 , where the last uncertainty is due to those on the branching fractions of the $${{J /\psi }} \!\rightarrow {p} {\overline{{p}}} $$ J/ψ→pp¯ and $${\eta _{c}} \!\rightarrow {p} {\overline{{p}}} $$ ηc→pp¯ decays. The difference between the $${J /\psi }$$ J/ψ and $${\eta _{c}} (1S)$$ ηc(1S) masses is also determined to be $$113.0 \pm 0.7 \pm 0.1 \, \text {MeV} $$ 113.0±0.7±0.1MeV , which is the most precise single measurement of this quantity to date.
Abstract The cross-sections of $$\psi {(2S)}$$ ψ(2S) meson production in proton-proton collisions at $$\sqrt{s} =13\text { TeV} $$ s=13TeV are measured with a data sample collected by the LHCb ...detector corresponding to an integrated luminosity of $$275\text { pb} ^{-1} $$ 275pb-1 . The production cross-sections for prompt $$\psi {(2S)}$$ ψ(2S) mesons and those for $$\psi {(2S)}$$ ψ(2S) mesons from b-hadron decays ($${\psi {(2S)}} \text{-from- }{b} $$ ψ(2S)-from-b ) are determined as functions of the transverse momentum, $$p_{\mathrm {T}}$$ pT , and the rapidity, y, of the $$\psi {(2S)}$$ ψ(2S) meson in the kinematic range $$2<p_{\mathrm {T}} <20\text { GeV/}c $$ 2<pT<20GeV/c and $$2.0<y<4.5$$ 2.0<y<4.5 . The production cross-sections integrated over this kinematic region are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},13\text { TeV})\\&\quad =1.430\pm 0.005\text { (stat)} \pm 0.099\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},13\text { TeV})\\&\quad =0.426\pm 0.002\text { (stat)} \pm 0.030\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$ σ(promptψ(2S),13TeV)=1.430±0.005(stat)±0.099(syst)μb,σ(ψ(2S)-from-b,13TeV)=0.426±0.002(stat)±0.030(syst)μb. A new measurement of $$\psi {(2S)}$$ ψ(2S) production cross-sections in pp collisions at $$\sqrt{s}=7\text { TeV} $$ s=7TeV is also performed using data collected in 2011, corresponding to an integrated luminosity of $$614\text { pb} ^{-1} $$ 614pb-1 . The integrated production cross-sections in the kinematic range $$3.5<p_{\mathrm {T}} <14\text { GeV/}c $$ 3.5<pT<14GeV/c and $$2.0<y<4.5$$ 2.0<y<4.5 are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},7\text { TeV})\\&\quad =0.471\pm 0.001\text { (stat)} \pm 0.025\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},7\text { TeV})\\&\quad =0.126\pm 0.001\text { (stat)} \pm 0.008\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$ σ(promptψ(2S),7TeV)=0.471±0.001(stat)±0.025(syst)μb,σ(ψ(2S)-from-b,7TeV)=0.126±0.001(stat)±0.008(syst)μb. All results show reasonable agreement with theoretical calculations.
Abstract A search for the rare leptonic decay $${{{B} ^+}} \!\rightarrow {\mu ^+} {\mu ^-} {\mu ^+} {{\upnu } _\mu } $$ B+→μ+μ-μ+νμ is performed using proton-proton collision data corresponding to an ...integrated luminosity of $$4.7 \, {\hbox {fb}}^{-1}$$ 4.7fb-1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two $${\mu ^+\mu ^-} $$ μ+μ- mass combinations is below $$980 {\mathrm {\,MeV\!/}c^2} $$ 980MeV/c2 . The data are consistent with the background-only hypothesis and an upper limit of $$1.6 \times 10^{-8}$$ 1.6×10-8 at 95% confidence level is set on the branching fraction in the stated kinematic region.
Abstract The decay-time-dependent $$CP$$ CP asymmetry in $${{B} ^0_{s}} \rightarrow J/\psi {{K} ^+} {{K} ^-} $$ Bs0→J/ψK+K- decays is measured using proton–proton collision data, corresponding to an ...integrated luminosity of $$1.9\,\mathrm{fb}^{-1} $$ 1.9fb-1 , collected with the LHCb detector at a centre-of-mass energy of $$13\,\mathrm {TeV}$$ 13TeV in 2015 and 2016. Using a sample of approximately 117 000 signal decays with an invariant $${{K} ^+} {{K} ^-} $$ K+K- mass in the vicinity of the $$\phi (1020)$$ ϕ(1020) resonance, the $$CP$$ CP -violating phase $$\phi _s$$ ϕs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $${{B} ^0_{s}} $$ Bs0 -$${{\overline{B}{}} {}^0_{s}} $$ B¯s0 system, $$\Delta \Gamma _s$$ ΔΓs . The difference of the average $${{B} ^0_{s}} $$ Bs0 and $${{B} ^0} $$ B0 meson decay widths, $$\Gamma _s-\Gamma _d$$ Γs-Γd , is determined using in addition a sample of $${{B} ^0} \rightarrow J/\psi {{K} ^+} {{\pi } ^-} $$ B0→J/ψK+π- decays. The values obtained are $$\phi _s = -0.083\pm 0.041\pm 0.006\mathrm { \,rad} $$ ϕs=-0.083±0.041±0.006rad , $$\Delta \Gamma _s = 0.077 \pm 0.008 \pm 0.003 {\mathrm { \,ps^{-1}}} $$ ΔΓs=0.077±0.008±0.003ps-1 and $$\Gamma _s-\Gamma _d = -0.0041 \pm 0.0024 \pm 0.0015{\mathrm { \,ps^{-1}}} $$ Γs-Γd=-0.0041±0.0024±0.0015ps-1 , where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of these quantities to date and are consistent with expectations based on the Standard Model and with a previous LHCb analysis of this decay using data recorded at centre-of-mass energies 7 and 8 TeV. Finally, the results are combined with recent results from $${{B} ^0_{s}} \rightarrow J/\psi {{\pi } ^+} {{\pi } ^-} $$ Bs0→J/ψπ+π- decays obtained using the same dataset as this analysis, and with previous independent LHCb results.
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