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Results for “BEAUTY MESONS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Search for decays of neutral beauty mesons into four muons

A search for the non-resonant decays B s 0 → μ + μ – μ + μ – and B 0 → μ + μ – μ + μ – is presented. The measurement is performed using the full Run 1 data set collected in proton-proton collisions by the LHCb experiment at the LHC. The data correspond to integrated luminosities of 1 and 2 fb –1 collected at centre-of-mass energies of 7 and 8 TeV, respectively. No signal is observed and upper limits on the branching fractions of the non-resonant decays at 95% confidence level are determined to be $\mathcal{B}$ (B$^{0}_{s}$→μ + μ – μ + μ – )< 2.5 × 10 –9 , (B 0 →μ + μ – μ + μ – )< 6.9 × 10 –10 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Measurement of beauty-strange meson production in Pb–Pb collisions at s NN = 5.02 TeV via non-prompt D s + mesons

The production yields of non-prompt ${D}^{+}_{s}$ mesons, namely ${D}^{+}_{s}$ mesons from beauty-hadron decays, were measured for the first time as a function of the transverse momentum ($p_T$) at midrapidity (|$y$| < 0.5) in central and semi-central Pb–Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s{NN}}$ = 5.02 TeV with the ALICE experiment at the LHC. The ${D}^{+}_{s}$ mesons and their charge conjugates were reconstructed from the hadronic decay channel ${D}^{+}_{s}$ → $φπ^+$, with $φ$ → K - K + , in the 4 < $p_T$ < 36 GeV/c and 2 < $p_T$ < 24 GeV/ $c$ intervals for the 0–10% and 30–50% centrality classes, respectively. The measured yields of non-prompt ${D}^{+}_{s}$ mesons are compared to those of prompt ${D}^{+}_{s}$ and non-prompt $D^0$ mesons by calculating the ratios of the production yields in Pb–Pb collisions and the nuclear modification factor $R_{AA}$. The ratio between the $R_{AA}$ of non-prompt ${D}^{+}_{s}$ prompt ${D}^{+}_{s}$ mesons, and that between the $R_{AA}$ of non-prompt ${D}^{+}_{s}$ and non-prompt $D^0$ mesons in central Pb–Pb collisions are found to be on average higher than unity in the 4 < $p_T$ < 12 GeV/ $c$ interval with a statistical significance of about 1.6σ and 1.7σ, respectively. The measured $R_{AA}$ ratios are compared with the predictions of theoretical models of heavy-quark transport in a hydrodynamically expanding QGP that incorporate hadronisation via quark recombination.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

First measurement of prompt and non-prompt D* + vector meson spin alignment in pp collisions at $\sqrt{s}$ = 13 TeV

This letter reports the first measurement of spin alignment, with respect to the helicity axis, for D* + vector mesons and their charge conjugates from charm-quark hadronisation (prompt) and from beauty meson decays (non-prompt) in hadron collisions. The measurements were performed at midrapidity (|y| < 0.8) as a function of transverse momentum (p T ) in proton–proton (pp) collisions collected by ALICE at the centre-of-mass energy $\sqrt{s}$ = 13 TeV. The diagonal spin density matrix element $ρ$00 of D* + mesons was measured from the angular distribution of the D* + → D 0 (→ K - π + )π + decay products, in the D* + rest frame, with respect to the D* + momentum direction in the pp centre of mass frame. The $ρ$00 value for prompt D* + mesons is consistent with 1/3, which implies no spin alignment. However, for non prompt D* + mesons an evidence of $ρ$00 larger than 1/3 is found. The measured value of the spin density element is $ρ$00 = 0.455±0.022(stat.)±0.035(syst.) in the 5 < p T < 20 GeV/c interval, which is consistent with a Pythia 8 Monte Carlo simulation coupled with the EvtGen package, which implements the helicity conservation in the decay of D* + meson from beauty mesons. In non-central heavy-ion collisions, the spin of the D* + mesons may be globally aligned with the direction of the initial angular momentum and magnetic field. Based on the results for pp collisions reported in this letter it is shown that alignment of non-prompt D* + mesons due to the helicity conservation coupled to the collective anisotropic expansion may mimic the signal of global spin alignment in heavy-ion collisions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Beauty vector meson decay constants from QCD sum rules

We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Heavy-Quark Mass and Heavy-Meson Decay Constants from QCD Sum Rules

We present a sum-rule extraction of decay constants of heavy mesons from the two-point correlator of heavy-light pseudoscalar currents. Our primary concern is to control the uncertainties of the decay constants, induced by both input QCD parameters and limited accuracy of the sum-rule method. Gaining this control is possible by applying our novel procedure for the extraction of hadron observables utilizing Borel-parameter-depending dual thresholds. For the charmed mesons, we obtain f{sub D} (206.2{+-}7.3{sub (OPE){+-}}5.1{sub (syst)}) MeV and f{sub D{sub s}} (245.3{+-}15.7{sub (OPE){+-}}4.5{sub (syst)}) MeV. In the case of the beauty mesons, the decay constants prove to be extremely sensitive to the exact value of the b-quark MS mass m-bar{sub b}(m-bar{sub b}). By matching our sum-rule prediction for f{sub B} to the lattice outcomes, the very accurate b-mass value m-bar{sub b}(m-bar{sub b}) = (4.245{+-}0.025) GeV is found, which yields f{sub B} = (193.4{+-}12.3{sub (OPE){+-}}4.3{sub (syst)}) MeV and f{sub B{sub s}} (232.5{+-}18.6{sub (OPE){+-}}2.4{sub (syst)}) MeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Search for $D^{*}(2007)^{0} \rightarrow \mu ^{+} \mu ^{-}$ in $B^{-}\rightarrow \pi ^{-} \mu ^{+} \mu ^{-}$ decays

The very rare D* (2007) 0 → μ + μ – decay is searched for by analysing B – → μ + μ – decays. The analysis uses a sample of beauty mesons produced in proton–proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb –1 . The signal signature corresponds to simultaneous peaks in the μ + μ – and π – μ + μ – invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at B (D* (2007) 0 → μ + μ – ) < 2.6 x 10 –8 at 90% confidence level. This is the first limit on the branching fraction of D* (2007) 0 → μ + μ – decays and the most stringent limit on D* (2007) 0 decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Higgs bosons in a minimal R-parity conserving left-right supersymmetric model

We revisit the Higgs sector of the left-right supersymmetric model. We study the scalar potential in a version of the model in which the minimum is the charge-conserving vacuum state, without R-parity violation or additional nonrenormalizable terms in the Lagrangian. We analyze the dependence of the potential and of the Higgs mass spectrum on the various parameters of the model, pinpointing the most sensitive ones. We also show that the model can predict light neutral flavor-conserving Higgs bosons, while the flavor-violating ones are heavy and within the limits from K{sup 0}-K{sup 0}, D{sup 0}-D{sup 0}, and B{sub d,s}{sup 0}-B{sub d,s}{sup 0} mixings. We study variants of the model in which at least one doubly charged Higgs boson is light and show that the parameter space for such Higgs masses and mixings is very restrictive, thus making the model more predictive.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Long-distance contribution to {Delta}{Gamma}{sub s} of the B{sub s}-B{sub s} system

We estimate the long-distance contribution to the width difference of the B{sub s}-B{sub s} system, based mainly on two-body D{sub s}{sup (*)}D{sub s}{sup (*)} modes and three-body D{sub s}{sup (*)}D{sup (*)}K{sup (*)} modes (and their CP conjugates). Some higher cs resonances are also considered. The contribution to {Delta}{Gamma}{sub s}/{Gamma}{sub s} by two-body modes is (10.2{+-}3.0)%, slightly smaller than the short-distance result of (13.3{+-}3.2)%. The contribution to {Delta}{Gamma}{sub s}/{Gamma}{sub s} by D{sub s0}*(2317), D{sub s1}(2460), and D{sub s1}(2536) resonances is negligible. For the three-body D{sub s}{sup (*)}D{sup (*)}K{sup (*)} modes, we adopt the factorization formalism and model the form factors with off-shell D{sub s}{sup (*)} poles, the D{sub sJ}(2700) resonance, and nonresonant contributions. These three-body modes can arise through current-produced or transition diagrams, but only SU(3)-related D{sub u,d}{sup (*)}D{sup (*)}K modes from the current diagram have been measured so far. The pole model results for D{sub u,d}*D{sup (*)}K agree well with the data, while D{sub u,d}D{sup (*)}K rates agree with the data only within a factor of 2 to 3. All measured D{sub u,d}{sup (*)}D{sup (*)}K rates can be reproduced by including nonresonant contributions. The total {Delta}{Gamma}{sub s}/{Gamma}{sub s} obtained is (16.7{+-}8.5)%, which agrees with the short-distance result within uncertainties. For illustration, we also demonstrate the effect of D{sub sJ}(2700) in modes with D{sup (*)}K{sup *}. In all scenarios, the total {Delta}{Gamma}{sub s}/{Gamma}{sub s} remain consistent with the short-distance result. Our results indicate that (a) the operator product expansion in the short-distance picture is a valid assumption, (b) approximating the B{sub s}{yields}D{sub s}{sup (*)}D{sub s}{sup (*)} decays to saturate {Delta}{Gamma}{sub s} has a large correction, (c) the effect of three-body modes cannot be neglected, and (d) in addition to the D{sub s} and D{sub s}* poles, the D{sub sJ}(2700) resonance also plays an important role in three-body modes. Future experiments are necessary to improve the estimation of {Delta}{Gamma}{sub s} from the long-distance point of view.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Hadronic absorption cross sections of B{sub c}

The cross sections of B{sub c} absorption by {pi} mesons are calculated using a hadronic Lagrangian based on the SU(5) flavor symmetry. Calculated cross sections are found to be in the ranges 2-7 mb and 0.2-2 mb for the processes B{sub c}{sup +}{pi}{yields}DB and B{sub c}{sup +}{pi}{yields}D*B*, respectively, when the monopole form factor is included. These results could be useful in calculating the production rate of B{sub c} mesons in relativistic heavy ion collisions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Quasiclassical theory of the Dirac equation with a scalar-vector interaction and its applications in the physics of heavy-light mesons

We construct a relativistic potential quark model of D, D{sub s}, B, and B{sub s} mesons in which the light quark motion is described by the Dirac equation with a scalar-vector interaction and the heavy quark is considered a local source of the gluon field. The effective interquark interaction is described by a combination of the perturbative one-gluon exchange potential V{sub Coul}(r)=-{xi}/r and the long-range Lorentz-scalar and Lorentz-vector linear potentials S{sub l.r.}(r)=(1-{lambda})({sigma}r+V{sub 0}) and V{sub l.r.}(r)={lambda}({sigma}r+V{sub 0}), where 0{<=}{lambda}<1/2. Within the quasiclassical approximation, we obtain simple asymptotic formulas for the energy and mass spectra and for the mean radii of D, D{sub s}, B, and B{sub s} mesons, which ensure a high accuracy of calculations even for states with the radial quantum number n{sub r{approx}}1. We show that the fine structure of P-wave states in heavy-light mesons is primarily sensitive to the choice of two parameters: the strong-coupling constant {alpha}{sub s} and the coefficient {lambda} of mixing of the long-range scalar and vector potentials S{sub l.r.}(r) and V{sub l.r.}(r). The quasiclassical formulas for asymptotic coefficients of wave functions at zero and infinity are obtained.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Associative production of B{sub c} and D mesons at the LHC

It is shown that the study of correlations in the associative production of B{sub c} and D mesons at LHC allows one to obtain essential information about the B{sub c} production mechanism.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Measurements of the branching fractions for B{sub (s)}{yields}D{sub (s)}{pi}{pi}{pi} and {Lambda}{sub b}{sup 0}{yields}{Lambda}{sub c}{sup +}{pi}{pi}{pi}

Branching fractions of the decays H{sub b}{yields}H{sub c}{pi}{sup -}{pi}{sup +}{pi}{sup -} relative to H{sub b}{yields}H{sub c}{pi}{sup -} are presented, where H{sub b} (H{sub c}) represents B{sup 0} (D{sup +}), B{sup -} (D{sup 0}), B{sub s}{sup 0} (D{sub s}{sup +}), and {Lambda}{sub b}{sup 0} ({Lambda}{sub c}{sup +}). The measurements are performed with the LHCb detector using 35 pb{sup -1} of data collected at {radical}(s)=7 TeV. The ratios of branching fractions are measured to be [B(B{sup 0}{yields}D{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})]/[B(B{sup 0}{yields}D{sup +}{pi}{sup -})]=2.38{+-}0.11{+-}0.21, [B(B{sup -}{yields}D{sup 0}{pi}{sup -}{pi}{sup +}{pi}{sup -})]/[B(B{sup -}{yields}D{sup 0}{pi}{sup -})]= 1.27{+-}0.06{+-}0.11, [B(B{sub s}{sup 0}{yields}D{sub s}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -})]/[B(B{sub s}{sup 0}{yields}D{sub s}{sup +}{pi}{sup -})]=2.01{+-}0.37{+-}0.20, [B({Lambda}{sub b}{sup 0}{yields}{Lambda}{sub c}{sup +}{pi}{sup -} {pi}{sup +}{pi}{sup -})]/[B({Lambda}{sub b}{sup 0}{yields}{Lambda}{sub c}{sup +}{pi}{sup -})]=1.43{+-}0.16{+-}0.13 We also report measurements of partial decay rates of these decays to excited charm hadrons. These results are of comparable or higher precision than existing measurements.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Lepton number violation in top quark and neutral B meson decays

Lepton number violation can be induced by Majorana neutrinos in four-body decays of the neutral B meson and the top quark. We study the effects of Majorana neutrinos in these |{Delta}L|=2 decays in a scenario where a single heavy neutrino can enhance the amplitude via the resonant mechanism. Using current bounds on heavy neutrino mixings, the most optimistic branching ratios turn out to be at the level of 10{sup -6} for B{sup 0}{yields}D{sup +}e{sup -}e{sup -}{pi}{sup +} and t{yields}bl{sup +}l{sup +}W{sup -} decays. Searches for these lepton number violation decays at future facilities can provide complementary constraints on masses and mixings of Majorana neutrinos.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Study of the pure annihilation B{sub c}{yields}A{sub 2}A{sub 3} decays

In this work, we calculate the CP-averaged branching ratios and the polarization fractions of the charmless hadronic B{sub c}{yields}A{sub 2}A{sub 3} decays within the framework of perturbative QCD (pQCD) approach, where A is either a light {sup 3}P{sub 1} or {sup 1}P{sub 1} axial-vector meson. These 32 decay modes can occur through the annihilation topology only. Based on the perturbative calculations and phenomenological analysis, we find the following results: (a) the branching ratios of the considered 32 B{sub c}{yields}A{sub 2}A{sub 3} decays are in the range of 10{sup -5} to 10{sup -8}; (b) B{sub c}{yields}a{sub 1}b{sub 1}, K{sub 1}{sup 0}K{sub 1}{sup +} and some other decays have sizable branching ratios and can be measured at the LHC experiments; (c) the branching ratios of B{sub c}{yields}A{sub 2}({sup 1}P{sub 1})A{sub 3}({sup 1}P{sub 1}) decays are generally much larger than those of B{sub c}{yields}A{sub 2}({sup 3}P{sub 1})A{sub 3}({sup 3}P{sub 1}) decays with a factor around (10{approx}100); (d) the branching ratios of B{sub c}{yields}K{sub 1}{sup 0}K{sub 1}{sup +} decays are sensitive to the value of {theta}{sub K}, which will be tested by the running LHC and forthcoming SuperB experiments; (e) the large longitudinal polarization contributions govern most considered decays and play the dominant role.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Semileptonic B and B{sub s} decays into orbitally excited charmed mesons

The BABAR Collaboration has recently reported products of branching fractions that include B meson semileptonic decays into final states with charged and neutral D{sub 1}(2420) and D{sub 2}*(2460), two narrow orbitally excited charmed mesons. We evaluate these branching fractions, together with those concerning D{sub 0}*(2400) and D{sub 1}{sup '}(2430) mesons, within the framework of a constituent quark model. The calculation is performed in two steps, one of which involves a semileptonic decay and the other is mediated by a strong process. Our results are in agreement with the experimental data. We also extend the study to semileptonic decays of B{sub s} into orbitally excited charmed-strange mesons, providing predictions to the possible measurements to be carried out at LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗