ORCID Profile
0000-0002-1191-3978
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Publisher: American Physical Society (APS)
Date: 22-09-2020
Publisher: Springer Science and Business Media LLC
Date: 06-2021
Abstract: A search is performed for rare and forbidden charm decays of the form $$ {D}_{(s)}^{+}\\to {h}^{\\pm }{\\mathrm{\\ell}}^{+}{\\mathrm{\\ell}}^{\\left(\\prime \\right)\\mp } $$ D s + → h ± ℓ + ℓ ′ ∓ , where h ± is a pion or kaon and ℓ (′)± is an electron or muon. The measurements are performed using proton-proton collision data, corresponding to an integrated luminosity of 1 . 6 fb − 1 , collected by the LHCb experiment in 2016. No evidence is observed for the 25 decay modes that are investigated and 90 % confidence level limits on the branching fractions are set between 1 . 4 × 10 − 8 and 6 . 4 × 10 − 6 . In most cases, these results represent an improvement on existing limits by one to two orders of magnitude.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 03-2021
DOI: 10.1140/EPJC/S10052-021-08973-5
Abstract: A search is performed for heavy neutrinos in the decay of a W boson into two muons and a jet. The data set corresponds to an integrated luminosity of approximately $$3.0\\, \\text {fb} ^{-1} $$ 3.0 fb - 1 of proton–proton collision data at centre-of-mass energies of 7 and $$8\\, \\text {TeV} $$ 8 TeV collected with the LHCb experiment. Both same-sign and opposite-sign muons in the final state are considered. Data are found to be consistent with the expected background. Upper limits on the coupling of a heavy neutrino with the Standard Model neutrino are set at $$95\\%$$ 95 % confidence level in the heavy-neutrino mass range from 5 to $$50\\, \\text {GeV/}c^2 $$ 50 GeV/ c 2 . These are of the order of $$10^{-3}$$ 10 - 3 for lepton-number-conserving decays and of the order of $$10^{-4}$$ 10 - 4 for lepton-number-violating heavy-neutrino decays.
Publisher: Springer Science and Business Media LLC
Date: 10-2020
DOI: 10.1140/EPJC/S10052-020-8365-0
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 s le 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.
Publisher: American Physical Society (APS)
Date: 27-11-2017
Publisher: American Physical Society (APS)
Date: 09-06-2021
Publisher: American Physical Society (APS)
Date: 17-12-2018
Publisher: American Physical Society (APS)
Date: 12-11-2020
Publisher: American Physical Society (APS)
Date: 12-10-2020
Publisher: American Physical Society (APS)
Date: 05-12-2017
Publisher: Springer Science and Business Media LLC
Date: 03-2021
DOI: 10.1140/EPJC/S10052-021-08994-0
Abstract: Long-lived particles decaying to $${e ^\\pm } {\\mu ^\\mp } {\\nu } $$ e ± μ ∓ ν , with masses between 7 and $$50 \\,\\text {GeV/}c^2 $$ 50 GeV/ c 2 and lifetimes between 2 and $$50 \\,\\text {ps} $$ 50 ps , are searched for by looking at displaced vertices containing electrons and muons of opposite charges. The search is performed using $$5.4 \\,\\text {fb} ^{-1} $$ 5.4 fb - 1 of $$p $$ p $$p $$ p collisions collected with the LHCb detector at a centre-of-mass energy of $$\\sqrt{s} = 13 \\,\\text {TeV} $$ s = 13 TeV . Three mechanisms of production of long-lived particles are considered: the direct pair production from quark interactions, the pair production from the decay of a Standard-Model-like Higgs boson with a mass of $$125 \\,\\text {GeV/}c^2 $$ 125 GeV/ c 2 , and the charged current production from an on-shell $$W $$ W boson with an additional lepton. No evidence of these long-lived states is obtained and upper limits on the production cross-section times branching fraction are set on the different production modes.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Springer Science and Business Media LLC
Date: 06-2021
Abstract: Searches for CP violation in the two-body decays $$ {D}_{(s)}^{+}\\to {h}^{+}{\\pi}^0 $$ D s + → h + π 0 and $$ {D}_{(s)}^{+}\\to {h}^{+}\\eta $$ D s + → h + η (where h + denotes a π + or K + meson) are performed using pp collision data collected by the LHCb experiment corresponding to either 9 fb − 1 or 6 fb − 1 of integrated luminosity. The π 0 and η mesons are reconstructed using the e + e − γ final state, which can proceed as three-body decays π 0 → e + e − γ and η → e + e − γ , or via the two-body decays π 0 → γγ and η → γγ followed by a photon conversion. The measurements are made relative to the control modes $$ {D}_{(s)}^{+}\\to {K}_{\\mathrm{S}}^0{h}^{+} $$ D s + → K S 0 h + to cancel the production and detection asymmetries. The CP asymmetries are measured to be $$ {\\displaystyle \\begin{array}{c}{\\mathcal{A}}_{CP}\\left({D}^{+}\\to {\\pi}^{+}{\\pi}^0\\right)=\\left(-1.3\\pm 0.9\\pm 0.6\\right)\\%,\\\\ {}{\\mathcal{A}}_{CP}\\left({D}^{+}\\to {K}^{+}{\\pi}^0\\right)=\\left(-3.2\\pm 4.7\\pm 2.1\\right)\\%,\\\\ {}\\begin{array}{c}{\\mathcal{A}}_{CP}\\left({D}^{+}\\to {\\pi}^{+}\\eta \\right)=\\left(-0.2\\pm 0.8\\pm 0.4\\right)\\%,\\\\ {}{\\mathcal{A}}_{CP}\\left({D}^{+}\\to {K}^{+}\\eta \\right)=\\left(-6\\pm 10\\pm 4\\right)\\%,\\\\ {}\\begin{array}{c}{\\mathcal{A}}_{CP}\\left({D}_s^{+}\\to {K}^{+}{\\pi}^0\\right)=\\left(-0.8\\pm 3.9\\pm 1.2\\right)\\%,\\\\ {}\\begin{array}{c}{\\mathcal{A}}_{CP}\\left({D}_s^{+}\\to {\\pi}^{+}\\eta \\right)=\\left(0.8\\pm 0.7\\pm 0.5\\right)\\%,\\\\ {}{\\mathcal{A}}_{CP}\\left({D}_s^{+}\\to {K}^{+}\\eta \\right)=\\left(0.9\\pm 3.7\\pm 1.1\\right)\\%,\\end{array}\\end{array}\\end{array}\\end{array}} $$ A CP D + → π + π 0 = − 1.3 ± 0.9 ± 0.6 % , A CP D + → K + π 0 = − 3.2 ± 4.7 ± 2.1 % , A CP D + → π + η = − 0.2 ± 0.8 ± 0.4 % , A CP D + → K + η = − 6 ± 10 ± 4 % , A CP D s + → K + π 0 = − 0.8 ± 3.9 ± 1.2 % , A CP D s + → π + η = 0.8 ± 0.7 ± 0.5 % , A CP D s + → K + η = 0.9 ± 3.7 ± 1.1 % , where the first uncertainties are statistical and the second systematic. These results are consistent with no CP violation and mostly constitute the most precise measurements of $$ {\\mathcal{A}}_{CP} $$ A CP in these decay modes to date.
Publisher: Springer Science and Business Media LLC
Date: 03-2021
Abstract: The time-dependent CP asymmetries of B 0 → π + π − and $$ {B}_s^0 $$ B s 0 → K + K − decays are measured using a data s le of pp collisions corresponding to an integrated luminosity of 1.9 fb − 1 , collected with the LHCb detector at a centre-of-mass energy of 13 TeV. The results are $$ {\\displaystyle \\begin{array}{c}{C}_{\\pi \\pi}=-0.311\\pm 0.045\\pm 0.015,\\\\ {}{S}_{\\pi \\pi}=-0.706\\pm 0.042\\pm 0.013,\\\\ {}{C}_{KK}=0.123\\pm 0.034\\pm 0.015,\\\\ {}{S}_{KK}=0.164\\pm 0.034\\pm 0.014,\\\\ {}{\\mathcal{A}}_{KK}^{\\Delta \\varGamma }=-0.83\\pm 0.05\\pm 0.09,\\end{array}} $$ C ππ = − 0.311 ± 0.045 ± 0.015 , S ππ = − 0.706 ± 0.042 ± 0.013 , C KK = 0.123 ± 0.034 ± 0.015 , S KK = 0.164 ± 0.034 ± 0.014 , A KK Δ Γ = − 0.83 ± 0.05 ± 0.09 , where the first uncertainties are statistical and the second systematic. The same data s le is used to measure the time-integrated CP asymmetries of B 0 → K + π − and $$ {B}_s^0 $$ B s 0 → K − π + decays and the results are $$ {\\displaystyle \\begin{array}{c}{A}_{CP}^{B^0}=-0.0824\\pm 0.0033\\pm 0.0033,\\\\ {}{A}_{CP}^{B_s^0}=0.236\\pm 0.013\\pm 0.011.\\end{array}} $$ A CP B 0 = − 0.0824 ± 0.0033 ± 0.0033 , A CP B s 0 = 0.236 ± 0.013 ± 0.011 . All results are consistent with earlier measurements. A combination of LHCb measurements provides the first observation of time-dependent CP violation in $$ {B}_s^0 $$ B s 0 decays.
Publisher: American Physical Society (APS)
Date: 02-12-2020
Publisher: American Physical Society (APS)
Date: 19-03-2015
Publisher: Springer Science and Business Media LLC
Date: 02-2021
Abstract: The decays $$ {\\mathrm{B}}_{\\mathrm{s}}^0 $$ B s 0 → J / ψπ + π − K + K − are studied using a data set corresponding to an integrated luminosity of 9 fb − 1 , collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The decays $$ {\\mathrm{B}}_{\\mathrm{s}}^0 $$ B s 0 → $$ \\mathrm{J}/{\\uppsi \\mathrm{K}}^{\\ast 0}{\\overline{\\mathrm{K}}}^{\\ast 0} $$ J / ψK ∗ 0 K ¯ ∗ 0 and $$ {\\mathrm{B}}_{\\mathrm{s}}^0 $$ B s 0 → χ c1 (3872)K + K − , where the K + K − pair does not originate from a ϕ meson, are observed for the first time. Precise measurements of the ratios of branching fractions between intermediate χ c1 (3872)ϕ, $$ \\mathrm{J}/{\\uppsi \\mathrm{K}}^{\\ast 0}{\\overline{\\mathrm{K}}}^{\\ast 0} $$ J / ψK ∗ 0 K ¯ ∗ 0 , ψ(2S)ϕ and χ c1 (3872)K + K − states are reported. A structure, denoted as X(4740), is observed in the J / ψϕ mass spectrum and, assuming a Breit-Wigner parameterisation, its mass and width are determined to be $$ {\\displaystyle \\begin{array}{c}{m}_{\\mathrm{X}(4740)}=4741\\pm 6\\pm 6\\kern0.5em \\mathrm{MeV}/{c}^2,\\\\ {}{\\Gamma}_{\\mathrm{X}(4740)}=53\\pm 15\\pm 11\\kern0.5em \\mathrm{MeV},\\end{array}} $$ m X 4740 = 4741 ± 6 ± 6 MeV / c 2 , Γ X 4740 = 53 ± 15 ± 11 MeV , where the first uncertainty is statistical and the second is systematic. In addition, the most precise single measurement of the mass of the $$ {\\mathrm{B}}_{\\mathrm{s}}^0 $$ B s 0 meson is performed and gives a value of $$ {m}_{{\\mathrm{B}}_{\\mathrm{s}}^0}=5366.98\\pm 0.07\\pm 0.13\\kern0.5em \\mathrm{MeV}/{c}^2. $$ m B s 0 = 5366.98 ± 0.07 ± 0.13 MeV / c 2 .
Publisher: American Physical Society (APS)
Date: 10-01-2018
Publisher: Springer Science and Business Media LLC
Date: 02-2021
Abstract: The inclusive $$ b\\overline{b} $$ b b ¯ - and $$ c\\overline{c} $$ c c ¯ -dijet production cross-sections in the forward region of pp collisions are measured using a data s le collected with the LHCb detector at a centre-of-mass energy of 13 TeV in 2016. The data s le corresponds to an integrated luminosity of 1.6 fb − 1 . Differential cross-sections are measured as a function of the transverse momentum and of the pseudorapidity of the leading jet, of the rapidity difference between the jets, and of the dijet invariant mass. A fiducial region for the measurement is defined by requiring that the two jets originating from the two b or c quarks are emitted with transverse momentum greater than 20 GeV/ c , pseudorapidity in the range 2 . 2 η 4 . 2, and with a difference in the azimuthal angle between the two jets greater than 1.5. The integrated $$ b\\overline{b} $$ b b ¯ -dijet cross-section is measured to be 53 . 0 ± 9 . 7 nb, and the total $$ c\\overline{c} $$ c c ¯ -dijet cross-section is measured to be 73 ± 16 nb. The ratio between $$ c\\overline{c} $$ c c ¯ - and $$ b\\overline{b} $$ b b ¯ -dijet cross-sections is also measured and found to be 1 . 37 ± 0 . 27. The results are in agreement with theoretical predictions at next-to-leading order.
Publisher: Springer Science and Business Media LLC
Date: 06-2021
Abstract: The first full angular analysis of the $$ {B}^0\\to {D}^{\\ast -}{D}_s^{\\ast +} $$ B 0 → D ∗ − D s ∗ + decay is performed using 6 fb − 1 of pp collision data collected with the LHCb experiment at a centre-of-mass energy of 13 TeV. The $$ {D}_s^{\\ast +}\\to {D}_s^{+}\\gamma $$ D s ∗ + → D s + γ and D * − → $$ {\\overline{D}}^0{\\pi}^{-} $$ D ¯ 0 π − vector meson decays are used with the subsequent $$ {D}_s^{+} $$ D s + → K + K − π + and $$ {\\overline{D}}^0 $$ D ¯ 0 → K + π − decays. All helicity litudes and phases are measured, and the longitudinal polarisation fraction is determined to be f L = 0 . 578 ± 0 . 010 ± 0 . 011 with world-best precision, where the first uncertainty is statistical and the second is systematic. The pattern of helicity litude magnitudes is found to align with expectations from quark-helicity conservation in B decays. The ratio of branching fractions [ℬ( $$ {B}^0\\to {D}^{\\ast -}{D}_s^{\\ast +} $$ B 0 → D ∗ − D s ∗ + ) × ℬ( $$ {D}_s^{\\ast +}\\to {D}_s^{+}\\gamma $$ D s ∗ + → D s + γ )] / ℬ( B 0 → D * − $$ {D}_s^{+} $$ D s + ) is measured to be 2 . 045 ± 0 . 022 ± 0 . 071 with world-best precision. In addition, the first observation of the Cabibbo-suppressed B s → D * − $$ {D}_s^{+} $$ D s + decay is made with a significance of seven standard deviations. The branching fraction ratio ℬ( B s → D * − $$ {D}_s^{+} $$ D s + ) / ℬ( B 0 → D * − $$ {D}_s^{+} $$ D s + ) is measured to be 0 . 049 ± 0 . 006 ± 0 . 003 ± 0 . 002, where the third uncertainty is due to limited knowledge of the ratio of fragmentation fractions.
Publisher: American Physical Society (APS)
Date: 25-01-2018
Publisher: American Physical Society (APS)
Date: 31-07-2020
Publisher: Springer Science and Business Media LLC
Date: 12-2020
Abstract: The shape of the $$ {B}_s^0\\to {D}_s^{\\ast -}{\\mu}^{+}{\\nu}_{\\mu } $$ B s 0 → D s ∗ − μ + ν μ differential decay rate is obtained as a function of the hadron recoil parameter using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb − 1 collected by the LHCb detector. The $$ {B}_s^0\\to {D}_s^{\\ast -}{\\mu}^{+}{\\nu}_{\\mu } $$ B s 0 → D s ∗ − μ + ν μ decay is reconstructed through the decays $$ {D}_s^{\\ast -}\\to {D}_s^{-}\\gamma $$ D s ∗ − → D s − γ and $$ {D}_s^{-}\\to {K}^{-}{K}^{+}{\\pi}^{-} $$ D s − → K − K + π − . The differential decay rate is fitted with the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) parametrisations of the form factors, and the relevant quantities for both are extracted.
Publisher: Springer Science and Business Media LLC
Date: 11-2020
Abstract: A search for the doubly heavy $$ {\\Xi}_{bc}^0 $$ Ξ bc 0 baryon using its decay to the D 0 pK – final state is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment between 2016 and 2018, corresponding to an integrated luminosity of 5.4 fb − 1 . No significant signal is found in the invariant mass range from 6.7 to 7.2 GeV/ c 2 . Upper limits are set at 95% credibility level on the ratio of the $$ {\\Xi}_{bc}^0 $$ Ξ bc 0 production cross-section times its branching fraction to D 0 pK − relative to that of the $$ {\\Lambda}_b^0\\to {D}^0{pK}^{-} $$ Λ b 0 → D 0 pK − decay. The limits are set as a function of the $$ {\\Xi}_{bc}^0 $$ Ξ bc 0 mass and lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and in the transverse momentum region from 5 to 25 GeV/ c . Upper limits range from 1 . 7 × 10 − 2 to 3 . 0 × 10 − 1 for the considered $$ {\\Xi}_{bc}^0 $$ Ξ bc 0 mass and lifetime hypotheses.
Publisher: Elsevier BV
Date: 04-2021
Publisher: IOP Publishing
Date: 04-2021
Abstract: A search for the rare decay is performed using collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb −1 . No significant signal of the decay is observed and an upper limit of at 90% confidence level is set on the branching fraction.
Publisher: Springer Science and Business Media LLC
Date: 13-05-2015
DOI: 10.1038/NATURE14474
Abstract: The standard model of particle physics describes the fundamental particles and their interactions via the strong, electromagnetic and weak forces. It provides precise predictions for measurable quantities that can be tested experimentally. The probabilities, or branching fractions, of the strange B meson (B(s)(0)) and the B0 meson decaying into two oppositely charged muons (μ+ and μ−) are especially interesting because of their sensitivity to theories that extend the standard model. The standard model predicts that the B(s)(0) →µ+µ− and B(0) →µ+µ− decays are very rare, with about four of the former occurring for every billion mesons produced, and one of the latter occurring for every ten billion B0 mesons. A difference in the observed branching fractions with respect to the predictions of the standard model would provide a direction in which the standard model should be extended. Before the Large Hadron Collider (LHC) at CERN started operating, no evidence for either decay mode had been found. Upper limits on the branching fractions were an order of magnitude above the standard model predictions. The CMS (Compact Muon Solenoid) and LHCb (Large Hadron Collider beauty) collaborations have performed a joint analysis of the data from proton–proton collisions that they collected in 2011 at a centre-of-mass energy of seven teraelectronvolts and in 2012 at eight teraelectronvolts. Here we report the first observation of the B(s)(0) → µ+µ− decay, with a statistical significance exceeding six standard deviations, and the best measurement so far of its branching fraction. Furthermore, we obtained evidence for the B(0) → µ+µ− decay with a statistical significance of three standard deviations. Both measurements are statistically compatible with standard model predictions and allow stringent constraints to be placed on theories beyond the standard model. The LHC experiments will resume taking data in 2015, recording proton–proton collisions at a centre-of-mass energy of 13 teraelectronvolts, which will approximately double the production rates of B(s)(0) and B0 mesons and lead to further improvements in the precision of these crucial tests of the standard model.
Publisher: American Physical Society (APS)
Date: 27-06-2013
Publisher: American Physical Society (APS)
Date: 08-09-2020
Publisher: Springer Science and Business Media LLC
Date: 05-2021
Abstract: The Cabibbo-suppressed decay $$ {\\Lambda}_{\\mathrm{b}}^0 $$ Λ b 0 → χ c1 pπ − is observed for the first time using data from proton-proton collisions corresponding to an integrated luminosity of 6 fb − 1 , collected with the LHCb detector at a centre-of-mass energy of 13 TeV. Evidence for the $$ {\\Lambda}_{\\mathrm{b}}^0 $$ Λ b 0 → χ c2 pπ − decay is also found. Using the $$ {\\Lambda}_{\\mathrm{b}}^0 $$ Λ b 0 → χ c1 pK − decay as normalisation channel, the ratios of branching fractions are measured to be $$ {\\displaystyle \\begin{array}{c}\\frac{\\mathcal{B}\\left({\\Lambda}_{\\mathrm{b}}^0\\to {\\upchi}_{\\mathrm{c}1}{\\mathrm{p}\\uppi}^{-}\\right)}{\\mathcal{B}\\left({\\Lambda}_{\\mathrm{b}}^0\\to {\\upchi}_{\\mathrm{c}1}{\\mathrm{p}\\mathrm{K}}^{-}\\right)}=\\left(6.59\\pm 1.01\\pm 0.22\\right)\\times {10}^{-2},\\\\ {}\\frac{\\mathcal{B}\\left({\\Lambda}_{\\mathrm{b}}^0\\to {\\upchi}_{\\mathrm{c}2}{\\mathrm{p}\\uppi}^{-}\\right)}{\\mathcal{B}\\left({\\Lambda}_{\\mathrm{b}}^0\\to {\\upchi}_{\\mathrm{c}1}{\\mathrm{p}\\uppi}^{-}\\right)}=0.95\\pm 0.30\\pm 0.04\\pm 0.04,\\\\ {}\\frac{\\mathcal{B}\\left({\\Lambda}_{\\mathrm{b}}^0\\to {\\upchi}_{\\mathrm{c}2}{\\mathrm{p}\\mathrm{K}}^{-}\\right)}{\\mathcal{B}\\left({\\Lambda}_{\\mathrm{b}}^0\\to {\\upchi}_{\\mathrm{c}1}{\\mathrm{p}\\mathrm{K}}^{-}\\right)}=1.06\\pm 0.05\\pm 0.04\\pm 0.04,\\end{array}} $$ B Λ b 0 → χ c 1 pπ − B Λ b 0 → χ c 1 pK − = 6.59 ± 1.01 ± 0.22 × 10 − 2 , B Λ b 0 → χ c 2 pπ − B Λ b 0 → χ c 1 pπ − = 0.95 ± 0.30 ± 0.04 ± 0.04 , B Λ b 0 → χ c 2 pK − B Λ b 0 → χ c 1 pK − = 1.06 ± 0.05 ± 0.04 ± 0.04 , where the first uncertainty is statistical, the second is systematic and the third is due to the uncertainties in the branching fractions of χ c1 , 2 → J / ψγ decays.
Publisher: American Physical Society (APS)
Date: 25-02-2021
Publisher: Springer Science and Business Media LLC
Date: 10-2020
Abstract: Searches are performed for a low-mass dimuon resonance, X , produced in proton-proton collisions at a center-of-mass energy of 13 TeV, using a data s le corresponding to an integrated luminosity of 5.1 fb − 1 and collected with the LHCb detector. The X bosons can either decay promptly or displaced from the proton-proton collision, where in both cases the requirements placed on the event and the assumptions made about the production mechanisms are kept as minimal as possible. The searches for promptly decaying X bosons explore the mass range from near the dimuon threshold up to 60 GeV, with nonnegligible X widths considered above 20 GeV. The searches for displaced X → μ + μ − decays consider masses up to 3 GeV. None of the searches finds evidence for a signal and 90% confidence-level exclusion limits are placed on the X → μ + μ − cross sections, each with minimal model dependence. In addition, these results are used to place world-leading constraints on GeV-scale bosons in the two-Higgs-doublet and hidden-valley scenarios.
Publisher: American Physical Society (APS)
Date: 20-02-2020
Publisher: Elsevier BV
Date: 06-2017
Publisher: American Physical Society (APS)
Date: 04-06-2020
Publisher: Springer Science and Business Media LLC
Date: 02-2013
Abstract: We search for CP violation in the decay ${D^{+}}\\to K_S^0{K^{+}}$ using a data s le with an integrated luminosity of 977 fb −1 collected with the Belle detector at the KEKB e + e − asymmetric-energy collider. No CP violation has been observed and the CP asymmetry in ${D^{+}}\\to K_S^0{K^{+}}$ decay is measured to be (−0.25 ± 0.28 ± 0.14)%, which is the most sensitive measurement to date. After subtracting CP violation due to ${K^0}-{{\\overline{K}}^0}$ mixing, the CP asymmetry in ${D^{+}}\\to {{\\overline{K}}^0}{K^{+}}$ decay is found to be (+0.08 ± 0.28 ± 0.14)%.
Publisher: Springer Science and Business Media LLC
Date: 04-2021
Abstract: Measurements of CP observables in B ± → D (*) K ± and B ± → D (*) π ± decays are presented, where D (∗) indicates a neutral D or D ∗ meson that is an admixture of meson and anti-meson states. Decays of the D (∗) meson to the Dπ 0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon. Decays of the D meson are reconstructed in the K ± π ∓ , K + K − , and π + π − final states. The analysis uses a s le of charged B mesons produced in proton-proton collisions and collected with the LHCb experiment, corresponding to integrated luminosities of 2.0, 1.0, and 5.7 fb − 1 taken at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The measurements of partially reconstructed B ± → D (*) K ± and B ± → D (∗) π ± with D → K ∓ π ± decays are the first of their kind, and a first observation of the B ± → $$ {\\left(D{\\pi}^0\\right)}_{D^{\\ast }}{\\pi}^{\\pm } $$ D π 0 D ∗ π ± decay is made with a significance of 6.1 standard deviations. All CP observables are measured with world-best precision, and in combination with other LHCb results will provide strong constraints on the CKM angle γ .
Publisher: American Physical Society (APS)
Date: 07-12-2020
Publisher: American Physical Society (APS)
Date: 09-03-2018
Publisher: American Physical Society (APS)
Date: 20-11-2020
Publisher: American Physical Society (APS)
Date: 22-04-2021
Publisher: American Physical Society (APS)
Date: 21-03-2016
Publisher: American Physical Society (APS)
Date: 06-01-2021
Publisher: American Physical Society (APS)
Date: 09-04-2018
Publisher: Springer Science and Business Media LLC
Date: 08-2020
Abstract: The decays B + → J / ψπ + π − K + are studied using a data set corresponding to an integrated luminosity of 9 fb − 1 collected with the LHCb detector in proton-proton collisions between 2011 and 2018. Precise measurements of the ratios of branching fractions with the intermediate ψ 2 (3823), χ c1 (3872) and ψ(2S) states are reported. The values are $$ {\\displaystyle \\begin{array}{c}\\frac{{\\mathcal{B}}_{{\\mathrm{B}}^{+}\\to {\\uppsi}_2(3823){\\mathrm{K}}^{+}}\\times {\\mathcal{B}}_{\\uppsi_2(3823)\\to \\mathrm{J}/{\\uppsi \\uppi}^{+}{\\uppi}^{-}}}{{\\mathcal{B}}_{{\\mathrm{B}}^{+}\\to {\\upchi}_{\\mathrm{c}1}(3872){\\mathrm{K}}^{+}}\\times {\\mathcal{B}}_{\\upchi_{\\mathrm{c}1}(3872)\\to \\mathrm{J}/{\\uppsi \\uppi}^{+}{\\uppi}^{-}}}=\\left(3.56\\pm 0.67\\pm 0.11\\right)\\times {10}^{-2},\\\\ {}\\frac{{\\mathcal{B}}_{{\\mathrm{B}}^{+}\\to {\\uppsi}_2(3823){\\mathrm{K}}^{+}}\\times {\\mathcal{B}}_{\\uppsi_2(3823)\\to \\mathrm{J}/{\\uppsi \\uppi}^{+}{\\uppi}^{-}}}{{\\mathcal{B}}_{{\\mathrm{B}}^{+}\\to \\uppsi \\left(2\\mathrm{S}\\right){\\mathrm{K}}^{+}}\\times {\\mathcal{B}}_{\\uppsi \\left(2\\mathrm{S}\\right)\\to \\mathrm{J}/{\\uppsi \\uppi}^{+}{\\uppi}^{-}}}=\\left(1.31\\pm 0.25\\pm 0.04\\right)\\times {10}^{-3},\\\\ {}\\frac{{\\mathcal{B}}_{\\mathrm{B}+\\to {\\upchi}_{\\mathrm{c}1}(3872){\\mathrm{K}}^{+}}\\times {\\mathcal{B}}_{\\upchi_{\\mathrm{c}1}(3872)\\to \\mathrm{J}/{\\uppsi \\uppi}^{+}{\\uppi}^{-}}}{{\\mathcal{B}}_{{\\mathrm{B}}^{+}\\to \\uppsi \\left(2\\mathrm{S}\\right){\\mathrm{K}}^{+}}\\times {\\mathcal{B}}_{\\uppsi \\left(2\\mathrm{S}\\right)\\to \\mathrm{J}/{\\uppsi \\uppi}^{+}{\\uppi}^{-}}}=\\left(3.69\\pm 0.07\\pm 0.06\\right)\\times {10}^{-2},\\end{array}} $$ B B + → ψ 2 3823 K + × B ψ 2 3823 → J / ψπ + π − B B + → χ c 1 3872 K + × B χ c 1 3872 → J / ψπ + π − = 3.56 ± 0.67 ± 0.11 × 10 − 2 , B B + → ψ 2 3823 K + × B ψ 2 3823 → J / ψπ + π − B B + → ψ 2 S K + × B ψ 2 S → J / ψπ + π − = 1.31 ± 0.25 ± 0.04 × 10 − 3 , B B + → χ c 1 3872 K + × B χ c 1 3872 → J / ψπ + π − B B + → ψ 2 S K + × B ψ 2 S → J / ψπ + π − = 3.69 ± 0.07 ± 0.06 × 10 − 2 , where the first uncertainty is statistical and the second is systematic. The decay of B + → ψ 2 (3823)K + with ψ 2 (3823) → J / ψπ + π − is observed for the first time with a significance of 5.1 standard deviations. The mass differences between the ψ 2 (3823), χ c1 (3872) and ψ(2S) states are measured to be $$ {\\displaystyle \\begin{array}{c}{m}_{\\upchi_{\\mathrm{c}1}(3872)}-{m}_{\\uppsi_2(3823)}=47.50\\pm 0.53\\pm 0.13\\ \\mathrm{MeV}/{c}^2,\\\\ {}{m}_{\\uppsi_2(3823)}-{m}_{\\uppsi_2\\left(2\\mathrm{S}\\right)}=137.98\\pm 0.53\\pm 0.14\\ \\mathrm{MeV}/{c}^2,\\\\ {}{m}_{\\upchi_{\\mathrm{c}1}(3872)}-{m}_{\\uppsi_2\\left(2\\mathrm{S}\\right)}=185.49\\pm 0.06\\pm 0.03\\ \\mathrm{MeV}/{c}^2,\\end{array}} $$ m χ c 1 3872 − m ψ 2 3823 = 47.50 ± 0.53 ± 0.13 MeV / c 2 , m ψ 2 3823 − m ψ 2 2 S = 137.98 ± 0.53 ± 0.14 MeV / c 2 , m χ c 1 3872 − m ψ 2 2 S = 185.49 ± 0.06 ± 0.03 MeV / c 2 , resulting in the most precise determination of the χ c1 (3872) mass. The width of the ψ 2 (3823) state is found to be below 5.2 MeV at 90% confidence level. The Breit-Wigner width of the χ c1 (3872) state is measured to be $$ {\\Gamma}_{\\upchi_{\\mathrm{c}1}(3872)}^{\\mathrm{BW}}={0.96}_{-0.18}^{+0.19}\\pm 0.21\\ \\mathrm{MeV} $$ Γ χ c 1 3872 BW = 0.96 − 0.18 + 0.19 ± 0.21 MeV which is inconsistent with zero by 5.5 standard deviations.
Publisher: Springer Science and Business Media LLC
Date: 12-2020
Abstract: A measurement of four branching-fraction ratios for three-body decays of B mesons involving two open-charm hadrons in the final state is presented. Run 1 and Run 2 pp collision data are used, recorded by the LHCb experiment at centre-of-mass energies 7, 8, and 13 TeV and corresponding to an integrated luminosity of 9 fb − 1 . The measured branching-fraction ratios are $$ {\\displaystyle \\begin{array}{c}\\frac{\\mathcal{B}\\left({B}^{+}\\to {D}^{\\ast +}{D}^{-}{K}^{+}\\right)}{\\mathcal{B}\\left({B}^{+}\\to {\\overline{D}}^0{D}^0{K}^{+}\\right)}=0.517\\pm 0.015\\pm 0.013\\pm 0.011,\\\\ {}\\frac{\\mathcal{B}\\left({B}^{+}\\to {D}^{\\ast -}{D}^{+}{K}^{+}\\right)}{\\mathcal{B}\\left({B}^{+}\\to {\\overline{D}}^0{D}^0{K}^{+}\\right)}=0.577\\pm 0.016\\pm 0.013\\pm 0.013,\\\\ {}\\begin{array}{c}\\frac{\\mathcal{B}\\left({B}^0\\to {D}^{\\ast -}{D}^0{K}^{+}\\right)}{\\mathcal{B}\\left({B}^0\\to {D}^{-}{D}^0{K}^{+}\\right)}=1.754\\pm 0.028\\pm 0.016\\pm 0.035,\\\\ {}\\frac{\\mathcal{B}\\left({B}^{+}\\to {D}^{\\ast +}{D}^{-}{K}^{+}\\right)}{\\mathcal{B}\\left({B}^{+}\\to {D}^{\\ast -}{D}^{+}{K}^{+}\\right)}=0.907\\pm 0.033\\pm 0.014,\\end{array}\\end{array}} $$ B B + → D ∗ + D − K + B B + → D ¯ 0 D 0 K + = 0.517 ± 0.015 ± 0.013 ± 0.011 , B B + → D ∗ − D + K + B B + → D ¯ 0 D 0 K + = 0.577 ± 0.016 ± 0.013 ± 0.013 , B B 0 → D ∗ − D 0 K + B B 0 → D − D 0 K + = 1.754 ± 0.028 ± 0.016 ± 0.035 , B B + → D ∗ + D − K + B B + → D ∗ − D + K + = 0.907 ± 0.033 ± 0.014 , where the first of the uncertainties is statistical, the second systematic, and the third is due to the uncertainties on the D -meson branching fractions. These are the most accurate measurements of these ratios to date.
Publisher: American Physical Society (APS)
Date: 02-03-2021
Publisher: American Physical Society (APS)
Date: 26-03-2021
Publisher: American Physical Society (APS)
Date: 11-09-2019
Publisher: WORLD SCIENTIFIC
Date: 08-2020
Publisher: American Physical Society (APS)
Date: 07-12-2020
Publisher: Elsevier BV
Date: 07-2016
Publisher: Springer Science and Business Media LLC
Date: 03-2021
Abstract: The CKM angle γ is measured for the first time from mixing-induced CP violation between $$ {B}_s^0\\to {D}_s^{\\mp }{K}^{\\pm }{\\pi}^{\\pm }{\\pi}^{\\mp } $$ B s 0 → D s ∓ K ± π ± π ∓ and $$ {\\overline{B}}_s^0\\to {D}_s^{\\pm }{K}^{\\mp }{\\pi}^{\\mp }{\\pi}^{\\pm } $$ B ¯ s 0 → D s ± K ∓ π ∓ π ± decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb − 1 recorded with the LHCb detector. A time-dependent litude analysis is performed to extract the CP -violating weak phase γ − 2 β s and, subsequently, γ by taking the $$ {B}_s^0\\hbox{-} {\\overline{B}}_s^0 $$ B s 0 ‐ B ¯ s 0 mixing phase β s as an external input. The measurement yields γ = (44 ± 12)° modulo 180°, where statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields $$ \\gamma =\\left({44}_{-13}^{+20}\\right){}^{\\circ} $$ γ = 44 − 13 + 20 ° modulo 180°. Moreover, the $$ {B}_s^0\\hbox{-} {\\overline{B}}_s^0 $$ B s 0 ‐ B ¯ s 0 oscillation frequency is measured from the flavour-specific control channel $$ {B}_s^0\\to {D}_s^{-}{\\pi}^{+}{\\pi}^{+}{\\pi}^{-} $$ B s 0 → D s − π + π + π − to be ∆ m s = (17 . 757 ± 0 . 007(stat) ± 0 . 008(syst)) ps − 1 , consistent with and more precise than the current world-average value.
Publisher: American Physical Society (APS)
Date: 22-12-2020
Publisher: Springer Science and Business Media LLC
Date: 03-2021
Abstract: A search for the $$ {B}_{\\mathrm{s}}^0 $$ B s 0 → D *± D ∓ decay is performed using proton-proton collision data at centre-of-mass energies of 7, 8 and 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb − 1 . The decay is observed with a high significance and its branching fraction relative to the B 0 → D *± D ∓ decay is measured to be $$ \\frac{\\mathrm{\\mathcal{B}}\\left({B}_s^0\\to {D}^{\\ast \\pm }{D}^{\\mp}\\right)}{\\left({B}^0\\to {D}^{\\ast \\pm }{D}^{\\mp}\\right)}=0.137\\pm 0.017\\pm 0.002\\pm 0.006, $$ ℬ B s 0 → D ∗ ± D ∓ B 0 → D ∗ ± D ∓ = 0.137 ± 0.017 ± 0.002 ± 0.006 , where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the ratio of the $$ {B}_{\\mathrm{s}}^0 $$ B s 0 and B 0 hadronisation fractions.
Publisher: American Physical Society (APS)
Date: 13-03-2018
Publisher: American Physical Society (APS)
Date: 18-12-2020
Publisher: Springer Science and Business Media LLC
Date: 11-2014
Publisher: Springer Science and Business Media LLC
Date: 02-2021
Abstract: A measurement of CP -violating observables is performed using the decays B ± → DK ± and B ± → Dπ ± , where the D meson is reconstructed in one of the self-conjugate three-body final states $$ {K}_{\\mathrm{S}}^0 $$ K S 0 π + π − and $$ {K}_{\\mathrm{S}}^0 $$ K S 0 K + K − (commonly denoted $$ {K}_{\\mathrm{S}}^0 $$ K S 0 h + h − ). The decays are analysed in bins of the D -decay phase space, leading to a measurement that is independent of the modelling of the D -decay litude. The observables are inter- preted in terms of the CKM angle γ . Using a data s le corresponding to an integrated luminosity of 9 fb − 1 collected in proton-proton collisions at centre-of mass energies of 7, 8, and 13 TeV with the LHCb experiment, γ is measured to be $$ \\left({68.7}_{-5.1}^{+5.2}\\right){}^{\\circ} $$ 68.7 − 5.1 + 5.2 ° . The hadronic parameters $$ {r}_B^{D K},{r}_B^{D\\pi},{\\delta}_B^{D K},\\kern0.5em \\mathrm{and}\\kern0.5em {\\delta}_B^{D\\pi} $$ r B DK , r B Dπ , δ B DK , and δ B Dπ , which are the ratios and strong-phase differences of the suppressed and favoured B ± decays, are also reported.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Oxford University Press (OUP)
Date: 02-2018
DOI: 10.1093/PTEP/PTY003
Publisher: American Physical Society (APS)
Date: 18-07-2018
Publisher: American Physical Society (APS)
Date: 05-03-2021
Publisher: Springer Science and Business Media LLC
Date: 12-2020
Abstract: An angular analysis of the B 0 → K* 0 e + e − decay is performed using a data s le corresponding to an integrated luminosity of 9 fb − 1 of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared ( q 2 ) interval between 0 . 0008 and 0 . 257 GeV 2 , where the rate is dominated by the B 0 → K * 0 γ transition with a virtual photon. The fraction of longitudinal polarisation of the K * 0 meson, F L , is measured to be F L = (4 . 4 ± 2 . 6 ± 1 . 4)%, where the first uncertainty is statistical and the second systematic. The $$ {A}_{\\mathrm{T}}^{\\mathrm{Re}} $$ A T Re observable, which is related to the lepton forward-backward asymmetry, is measured to be $$ {A}_{\\mathrm{T}}^{\\mathrm{Re}} $$ A T Re = − 0 . 06 ± 0 . 08 ± 0 . 02. The $$ {A}_{\\mathrm{T}}^{(2)} $$ A T 2 and $$ {A}_{\\mathrm{T}}^{\\mathrm{Im}} $$ A T Im transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be $$ {A}_{\\mathrm{T}}^{(2)} $$ A T 2 = 0 . 11 ± 0 . 10 ± 0 . 02 and $$ {A}_{\\mathrm{T}}^{\\mathrm{Im}} $$ A T Im = 0 . 02 ± 0 . 10 ± 0 . 01. The results are consistent with Standard Model predictions and provide the world’s best constraint on the b → sγ photon polarisation.
Publisher: Elsevier BV
Date: 10-2013
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Deepanwita Dutta.