scholarly journals Observation of CP violation in two-body $$ {B}_{(s)}^0 $$-meson decays to charged pions and kaons

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Cp Violation ◽  
Time Dependent ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Meson Decays ◽  
Charged Pions ◽  
Lhcb Detector ◽  
Integrated Luminosity

Abstract The time-dependent CP asymmetries of B0→ π+π− and $$ {B}_s^0 $$ B s 0 → K+K− decays are measured using a data sample 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 sample is used to measure the time-integrated CP asymmetries of B0→ 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.

scholarly journals Measurement of the shape of the $$ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $$ differential decay rate

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Decay Rate ◽  
Form Factors ◽  
Proton Collision ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Proton Proton ◽  
Lhcb Detector ◽  
Proton Proton Collision ◽  
Integrated Luminosity

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.

scholarly journals Search for an LSP Gluino from Stop Decay

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 804-806
Author(s):  
PATRICE VERDIER
Keyword(s):  
Standard Model ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Delphi Detector ◽  
The Standard Model ◽  
Model Predictions ◽  
Supersymmetric Models ◽  
Integrated Luminosity

In some supersymmetric models, the gluino [Formula: see text] could be light and stable, and would hadronize to form R-hadrons. Data collected by the DELPHI detector at centre-of-mass energy from 189 to 202 GeV corresponding to an integrated luminosity of 384 pb -1 have been used to search for R-hadrons from stop decay. The observed number of events is in agreement with the Standard Model predictions. Results are presented in terms of excluded regions in the plane [Formula: see text]

Measurements of Time-Dependent CP Violation in Radiative B Meson Decays at BABAR

2010 ◽  
Author(s):  
A. Lazzaro ◽  
George Alverson ◽  
Pran Nath ◽  
Brent Nelson ◽  
Keyword(s):  
Cp Violation ◽  
B Meson ◽  
Time Dependent ◽  
B Meson Decays ◽  
Meson Decays

scholarly journals Measurements of the Higgs H(125) boson at CMS

2018 ◽  
Vol 182 ◽  
pp. 02018
Author(s):  
Valeria Botta
Keyword(s):  
Higgs Boson ◽  
Large Hadron Collider ◽  
Hadron Collider ◽  
Top Quarks ◽  
Final States ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Associated Production ◽  
Cms Detector ◽  
Integrated Luminosity

The most recent measurements of the Higgs H(125) boson in several final states, including decays to bosons, fermions, and the associated production of a Higgs boson with top quarks, are reviewed. Results have been obtained analysing the protonproton collision data collected with the CMS detector at the Large Hadron Collider (LHC) in 2016, corresponding to an integrated luminosity of 35.9 fb-1 at a centre-of-mass energy of 13 TeV.

scholarly journals Observation of the decay $$ {\Lambda}_{\mathrm{b}}^0 $$ → χc1pπ−

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Branching Fractions ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Proton Proton ◽  
Proton Collisions ◽  
Lhcb Detector ◽  
Using Data ◽  
Cabibbo Suppressed ◽  
First Time ◽  
Proton Proton Collisions

Abstract The Cabibbo-suppressed decay $$ {\Lambda}_{\mathrm{b}}^0 $$ Λ b 0 → χc1pπ− 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 → χc2pπ− decay is also found. Using the $$ {\Lambda}_{\mathrm{b}}^0 $$ Λ b 0 → χc1pK− 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 χc1,2→ J/ψγ decays.

RECENT RESULTS ON CP VIOLATION IN B DECAY

2005 ◽  
Vol 20 (22) ◽  
pp. 5069-5079 ◽  
Author(s):  
M. A. GIORGI
Keyword(s):  
Cp Violation ◽  
Center Of Mass ◽  
Neutral Kaon ◽  
Time Dependent ◽  
Mass Energy ◽  
Kaon Decay ◽  
Decay Channels ◽  
Center Of Mass Energy ◽  
Initial Discovery ◽  
Time Dependent Analysis

This paper, 40 years after the discovery of CP violation 1 in neutral kaon decay in the famous experiment of Brookhaven, presents the most recent results on the CP violation in the b sector as come out of the experiments BABAR and BELLE that are taking data since 1999 at PEPII and KEKB e+e- asymmetric B -Factories operating at the center of mass energy corresponding to the mass of the ϒ4S. After their initial discovery of the CP violation and the measurement of sin2β in 2001 2, now is the time of the observation of direct CP violation by BABAR, confirmed by BELLE, the initial measurements of α, the first clue of γ and the very intriguing results about the measurements of sin2β in the time dependent analysis of decay channels via penguin loops, where [Formula: see text] and [Formula: see text].

scholarly journals Top FCNC searches at HL-LHC with the CMS experiment

2018 ◽  
Vol 191 ◽  
pp. 02009 ◽  
Author(s):  
Petr Mandrik ◽  
Keyword(s):  
Cross Sections ◽  
Top Quark ◽  
Neutral Current ◽  
Hadron Collider ◽  
Particle Accelerator ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Flavor Change Neutral Current ◽  
Cms Experiment ◽  
Integrated Luminosity

The Large Hadron Collider is the world’s largest and highest centerof- mass energy particle accelerator. During the Phase I operation it is expected that the LHC operated at a centre-of-mass energy of 13 TeV will deliver to the CMS experiment total integrated luminosity of ~300 fb-1 till 2023. The High Luminosity LHC upgrade is expected to run at a centre-of-mass energy of 14 TeV and will allow ATLAS and CMS to collect integrated luminosities of the order of 300 fb-1 per year, and up to 3000 fb-1 during the HL-LHC projected lifetime of ten years. The large expected integrated luminosity enables the exploration of the multi-TeV scale by searches for particles with high masses as well as by investigation of processes with very low cross sections such as Flavor-Change Neutral Current interactions in top quark sector. In this report we present a proposal for the top quark FCNC searches at HL-LHC based on Monte-Carlo simulation of the upgraded CMS detector.

scholarly journals J/ψ production in proton-lead collisions at 8 TeV with the LHCb detector

2018 ◽  
Vol 171 ◽  
pp. 19001
Author(s):  
Oleksandr Okhrimenko
Keyword(s):  
Transverse Momentum ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Nucleon Pair ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Nuclear Modification ◽  
Lhcb Detector ◽  
Nuclear Modification Factors ◽  
8 Tev

The production of J/ψ mesons is studied in proton-lead collisions at a centre-of-mass energy per nucleon pair [see formula in PDF] = 8.16 TeV with the LHCb detector. The double differential cross-sections of prompt and nonprompt J/ψ production are measured as functions of the J/ψ transverse momentum and rapidity. Nuclear modification factors are determined. The results are compared with different theoretical calculations.

scholarly journals Search for long-lived particles decaying to $$e ^\pm $$ $$\mu ^\mp $$ $$\nu $$

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Production Cross ◽  
Branching Fraction ◽  
Charged Current ◽  
Centre Of Mass ◽  
Mass Energy ◽  
Upper Limits ◽  
Lhcb Detector ◽  
Current Production

AbstractLong-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.

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