scholarly journals Updated search for $$ {B}_c^{+} $$ decays to two charm mesons

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
◽  
R. Aaij ◽  
A. S. W. Abdelmotteleb ◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
...  
Keyword(s):  
Branching Fractions ◽  
Final States ◽  
Charm Mesons ◽  
Data Set ◽  
Proton Proton ◽  
Neutral Pions ◽  
Proton Collisions ◽  
Decay Modes ◽  
Upper Limits ◽  
Proton Proton Collisions

Abstract A data set corresponding to an integrated luminosity of 9 fb−1 of proton-proton collisions collected by the LHCb experiment has been analysed to search for $$ {B}_c^{+}\to {D}_{(s)}^{\left(\ast \right)+}{\genfrac{}{}{0pt}{}{\left(\hbox{---} \right)}{D}}^{\left(\ast \right)0} $$ B c + → D s ∗ + — D ∗ 0 decays. The decays are fully or partially reconstructed, where one or two missing neutral pions or photons from the decay of an excited charm meson are allowed. Upper limits for the branching fractions, normalised to B+ decays to final states with similar topologies, are obtained for sixteen $$ {B}_c^{+} $$ B c + decay modes. For the decay $$ {B}_c^{+}\to {D}_s^{+}{\overline{D}}^0 $$ B c + → D s + D ¯ 0 , an excess with a significance of 3.4 standard deviations is found.

scholarly journals Study of $$ {\mathrm{B}}_{\mathrm{s}}^0 $$ → J/ψπ+π−K+K− decays

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Branching Fractions ◽  
Centre Of Mass ◽  
Single Measurement ◽  
Data Set ◽  
Proton Proton ◽  
Proton Collisions ◽  
A Value ◽  
Lhcb Detector ◽  
First Time ◽  
Proton Proton Collisions

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 → χc1(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 χc1(3872)ϕ, $$ \mathrm{J}/{\uppsi \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0} $$ J / ψK ∗ 0 K ¯ ∗ 0 , ψ(2S)ϕ and χc1(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 .

scholarly journals Search for decays of the 125 GeV Higgs boson into a Z boson and a ρ or ϕ meson

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Z Boson ◽  
Branching Fractions ◽  
Proton Collision ◽  
Data Set ◽  
Proton Proton ◽  
Decay Channels ◽  
Decay Products ◽  
Upper Limits ◽  
Z Boson Decays

Abstract Decays of the 125 GeV Higgs boson into a Z boson and a ρ0(770) or ϕ(1020) meson are searched for using proton-proton collision data collected by the CMS experiment at the LHC at $$ \sqrt{s} $$ s = 13 TeV. The analysed data set corresponds to an integrated luminosity of 137 fb−1. Events are selected in which the Z boson decays into a pair of electrons or a pair of muons, and the ρ and ϕ mesons decay into pairs of pions and kaons, respectively. No significant excess above the background model is observed. As different polarization states are possible for the decay products of the Z boson and ρ or ϕ mesons, affecting the signal acceptance, scenarios in which the decays are longitudinally or transversely polarized are considered. Upper limits at the 95% confidence level on the Higgs boson branching fractions into Zρ and Zϕ are determined to be 1.04–1.31% and 0.31–0.40%, respectively, where the ranges reflect the considered polarization scenarios; these values are 740–940 and 730–950 times larger than the respective standard model expectations. These results constitute the first experimental limits on the two decay channels.

scholarly journals STRUCTURE FUNCTIONS

2009 ◽  
Vol 24 (06) ◽  
pp. 1069-1086 ◽  
Author(s):  
CRISTINEL DIACONU
Keyword(s):  
Cross Sections ◽  
Structure Functions ◽  
Distribution Functions ◽  
Final States ◽  
Parton Distribution Functions ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Proton Collisions ◽  
Bjorken X ◽  
Proton Proton Collisions

Recent progress in the understanding of the nucleon is presented. The unpolarized structure functions are obtained with unprecedented precision from the combined H1 and ZEUS data and are used to extract proton parton distribution functions via NLO QCD fits. The obtained parametrization displays an improved precision, in particular at low Bjorken x, and leads to precise predictions of cross-sections for LHC phenomena. Recent data from proton–antiproton collisions at Tevatron indicate further precise constraints at large Bjorken x. The flavor content of the proton is further studied using final states with charm and beauty in DIS ep and [Formula: see text] collisions. Data from polarized DIS or proton–proton collisions are used to test the spin structure of the proton and to constrain the polarized parton distributions.

scholarly journals Search for black holes and other new phenomena in high-multiplicity final states in proton–proton collisions at s=13TeV

2017 ◽  
Vol 774 ◽  
pp. 279-307 ◽  
Author(s):  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
E. Asilar ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Black Holes ◽  
High Multiplicity ◽  
Final States ◽  
Proton Proton ◽  
Proton Collisions ◽  
New Phenomena ◽  
Proton Proton Collisions
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