BHLS 2 upgrade: τ spectra, muon HVP and the [ π 0 , η , η ' ] system.

The generic hidden local symmetry (HLS) model has recently given rise to its BHLS 2 variant, defined by introducing symmetry breaking mostly in the vector meson sector; the central mechanism is a modification of the covariant derivative at the root of the HLS approach. However, the description of the τ dipion spectra, especially the Belle one, is not fully satisfactory, whereas the simultaneous dealing with its annihilation sector ( e + e - → π + π - / π + π - π 0 / π 0 γ / η γ / K + K - / K L K S ) is optimum. We show that this issue is solved by means of an additional breaking term which also allows us to consistently include the mixing properties of the [ π 0 , η , η ' ] system within this extended BHLS 2 ( EBHLS 2 ) scope. This mechanism, an extension of the usual 't Hooft determinant term, only affects the kinetic energy part of the BHLS 2 Lagrangian. One thus obtains a fair account for the τ dipion spectra which complements the fair account of the annihilation channels already reached. The Belle dipion spectrum is found to provide evidence in favor of a violation of the conserved vector current (CVC) in the τ lepton decay; this evidence is enforced by imposing the conditions < 0 | J µ q | [ q ' q ' ¯ ] ( p ) > = i p µ f q δ q q ' , { [ q q ¯ ] , q = u , d , s } on EBHLS 2 axial current matrix elements. EBHLS 2 is found to recover the usual (completed) formulae for the [ π 0 , η , η ' ] mixing parameters, and the global fits return mixing parameter values in agreement with expectations and better uncertainties. Updating the muon hadronic vacuum polarization (HVP), one also argues that the strong tension between the KLOE and BaBar pion form factors imposes to provide two solutions, namely a µ H V P - L O ( KLOE ) = 687.48 ± 2.93 and a µ H V P - L O ( BaBar ) = 692.53 ± 2.95 , in units of 10 - 10 , rather than some combination of these. Taking into account common systematics, their differences from the experimental BNL-FNAL average value exhibit significance > 5.4 σ (KLOE) and > 4.1 σ (BaBar), with fit probabilities favoring the former.

Learning, teaching, and training in microsurgery: A systematic review.

Numerous microsurgical training techniques and materials have been developed to reduce animal use and training costs. This systematic review aimed to catalog the available microsurgery learning methods on non-living material in order to define an educational program. The PubMed database was searched for English and French articles related to the initial learning of microsurgery with inert, non-living, or digital material and containing the keywords "microsurgery", "non-living", "simulation" and "virtual reality". Among the 488 articles found, 82 were included. This work reports the main microsurgery learning supports. They were classified according to the material used: inert material, cadaveric animal tissues, human cadaver model, virtual reality, and digital technologies. The educational program proposes here is a two-step program that uses non-living material (basic and deepening) before progressing to living models. This initial learning phase teaches basic microsurgical skills (precision, tremor management, and magnification). Then, frequent home training sessions help to maintain the acquired skills. Ethical, organizational, and economic constraints limit access to animal models. Therefore, inert models seem to be ideal support for initial microsurgical learning. The multiplicity of models described makes it possible to achieve progressive learning depending on which models are available.

Can Assessment of the Tongue on Brain MRI Aid Differentiation of Seizure from Alternative Causes of Transient Loss of Consciousness?

BACKGROUND AND PURPOSE: Transient loss of consciousness is commonly evaluated in the emergency department. Although typically caused by epileptic seizure, syncope, or psychogenic nonepileptic seizure, the underlying etiology is frequently misdiagnosed. Lateral tongue bites are reportedly a specific clinical finding of seizure. We have observed tongue signal abnormality suggesting bite injury on brain MR imaging after seizures. We hypothesized an association between tongue signal abnormality and seizure diagnosis among patients in the emergency department imaged for transient loss of consciousness. Our purposes were to determine the prevalence of tongue signal abnormality among this population and the predictive performance for seizure diagnosis. MATERIALS AND METHODS: For this retrospective study including 82 brain MR imaging examinations, 2 readers independently assessed tongue signal abnormality on T2-weighted and T2-weighted FLAIR images. Discrepancies were resolved by consensus, and interrater reliability (Cohen κ) was calculated. The final diagnosis was recorded. Proportions were compared using the Fisher exact test. RESULTS: Tongue signal abnormality was present on 19/82 (23%) MR imaging examinations. Interrater reliability was "substantial" (κ = 0.77). Seizure was diagnosed among 18/19 (95%) patients with tongue signal abnormality and 29/63 (46%) patients without it (P < .001). In our cohort, tongue signal abnormality conveyed 97% specificity, 95% positive predictive value, and 63% accuracy for seizure diagnosis. CONCLUSIONS: Tongue signal abnormality was observed in 23% of the study cohort and conveyed 97% specificity and 95% positive predictive value for seizure diagnosis. By assessing and reporting tongue signal abnormality, radiologists may facilitate a timely and accurate diagnosis of seizure among patients imaged for transient loss of consciousness.

Determination of the X(3872) meson quantum numbers.

The quantum numbers of the X(3872) meson are determined to be J(PC)=1(++) based on angular correlations in B(+)→X(3872)K(+) decays, where X(3872)→π(+)π(-)J/ψ and J/ψ→µ(+)µ(-). The data correspond to 1.0 fb(-1) of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements J(PC)=2(-+) is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) state.

Search for rare B(0)((s))→µ(+)µ(-)µ(+)µ(-) decays.

A search for the decays B(0)((s))→µ(+)µ(-)µ(+)µ(-) and B(0)→µ(+)µ(-)µ(+)µ(-) is performed using data, corresponding to an integrated luminosity of 1.0 fb(-1), collected with the LHCb detector in 2011. The number of candidates observed is consistent with the expected background and, assuming phase-space models of the decays, limits on the branching fractions are set: B(B(s)(0)→µ(+)µ(-)µ(+)µ(-))<1.6(1.2)×10(-8) and B(B(0)→µ(+)µ(-)µ(+)µ(-))<6.6(5.3)×10(-9) at 95% (90%) confidence level. In addition, limits are set in the context of a supersymmetric model which allows for the B((s))(0) meson to decay into a scalar (S) and pseudoscalar particle (P), where S and P have masses of 2.5 GeV/c and 214.3 MeV/c, respectively, both resonances decay into µ(+)µ(-). The branching fraction limits for these decays are B(B(s)(0)→SP)<1.6(1.2)×10(-8) and B(B(0)→SP)<6.3(5.1)×10(-9) at 95% (90%) confidence level.

Measurement of the Λ(b)(0), Ξ (b)(-), and Ω(b((-) Baryon masses.

Bottom baryons decaying to a J/ψ meson and a hyperon are reconstructed using 1.0 fb(-1) of data collected in 2011 with the LHCb detector. Significant Λ(b)(0) → J/ψΛ, Ξ(b((-) → J/ψΞ(-) and Ω(b)(-) → J/ψΩ(-) signals are observed and the corresponding masses are measured to be M(Λ(b)(0))=5619.53 ± 0.13(stat.) ± 0.45(syst.) MeV/c(2), M(Ξ(b)(-)) = 5795.8 ± 0.9(stat.) ± 0.4(syst.) MeV/c(2), M(Ω(b)(-)) = 6046.0 ± 2.2(stat.) ± 0.5(syst.) MeV/c(2) , while the differences with respect to the Λ(b)(0) mass are M(Ξ(b)(-))-M(Λ(b)(0))=176.2 ± 0.9(stat.) ± 0.1(syst.) MeV/c(2), M(Ω(b)(-))-M(Λ(b)(0))=426.4 ± 2.2(stat.) ± 0.4(syst.) MeV/c(2). These are the most precise mass measurements of the Λ(b)(0), Ξ(b)(-) and Ω(b)(-) baryons to date. Averaging the above Λ(b)(0) mass measurement with that published by LHCb using 35 pb(-1) of data collected in 2010 yields M(Λ(b)(0)) = 5619.44 ± 0.13(stat.)± 0.38(syst.) MeV/c(2).

Observation of D0-D0 oscillations.

We report a measurement of the time-dependent ratio of D(0) → K(+) π- to D(0) → K(-) π(+) decay rates in D(*+)-tagged events using 1.0 fb(-1) of integrated luminosity recorded by the LHCb experiment. We measure the mixing parameters x('2) = (-0.9 ± 1.3) × 10(-4), y' = (7.2 ± 2.4) × 10(-3), and the ratio of doubly-Cabibbo-suppressed to Cabibbo-favored decay rates R(D) = (3.52 ± 0.15) × 10^{-3}, where the uncertainties include statistical and systematic sources. The result excludes the no-mixing hypothesis with a probability corresponding to 9.1 standard deviations and represents the first observation of D0-D0 oscillations from a single measurement.

First evidence for the decay B(s)(0)→µ+ µ-.

A search for the rare decays B(s)(0)→µ+ µ- and B(0)→µ+ µ- is performed with data collected in 2011 and 2012 with the LHCb experiment at the Large Hadron Collider. The data samples comprise 1.1 fb(-1) of proton-proton collisions at sqrt[s]=8 TeV and 1.0 fb(-1) at sqrt[s]=7 TeV. We observe an excess of B(s)(0)→µ+ µ- candidates with respect to the background expectation. The probability that the background could produce such an excess or larger is 5.3×10(-4) corresponding to a signal significance of 3.5 standard deviations. A maximum-likelihood fit gives a branching fraction of B(B(s)(0)→µ+ µ-)=(3.2(-1.2)(+1.5))×10(-9), where the statistical uncertainty is 95% of the total uncertainty. This result is in agreement with the standard model expectation. The observed number of B(0)→µ+ µ- candidates is consistent with the background expectation, giving an upper limit of B(B(0)→µ+ µ-)<9.4×10(-10) at 95% confidence level.

Measurement of the CP asymmetry in B(0)→K(*0)µ(+)µ(-) decays.

A measurement of the CP asymmetry in B(0)→K(*0)µ(+)µ(-) decays is presented, based on 1.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011. The measurement is performed in six bins of invariant mass squared of the µ(+)µ(-) pair, excluding the J/ψ and ψ(2S) resonance regions. Production and detection asymmetries are removed using the B(0)→J/ψK(*0) decay as a control mode. The integrated CP asymmetry is found to be -0.072±0.040(stat)±0.005(syst), consistent with the standard model.

First measurement of the CP-violating phase in Bs(0) → ϕϕ decays.

A first flavor-tagged measurement of the time-dependent CP-violating asymmetry in B(s)(0) → ϕϕ decays is presented. In this decay channel, the CP-violating weak phase arises due to CP violation in the interference between B(s)(0)-B(s)(0) mixing and the b → sss gluonic penguin decay amplitude. Using a sample of pp collision data corresponding to an integrated luminosity of 1.0 fb(-1) and collected at a center-of-mass energy of 7 TeV with the LHCb detector, 880 B(s)(0) → ϕϕ signal decays are obtained. The CP-violating phase is measured to be in the interval [-2.46,-0.76] rad at a 68% confidence level. The p value of the standard model prediction is 16%.

First observation of the decay Bs2*(5840)(0)→B*+ K- and studies of excited Bs(0) mesons.

The properties of the orbitally excited (L=1) Bs(0) states are studied by using 1.0 fb(-1) of pp collisions at sqrt[s]=7 TeV collected with the LHCb detector. The first observation of the Bs2*(5840)(0) meson decaying to B*+ K- is reported, and the corresponding branching fraction measured relative to the B+ K- decay mode. The Bs1(5830)(0)→B*+ K- decay is observed as well. The width of the Bs2*(5840)(0) state is measured for the first time, and the masses of the two states are determined with the highest precision to date. The observation of the Bs2*(5840)(0)→B*+ K- decay favors the spin-parity assignment J(P)=2+ for the Bs2*(5840)(0) meson. In addition, the most precise measurement of the mass difference m(B*+)-m(B+)=45.01±0.30(stat)±0.23(syst) MeV/c(2) is obtained.

Measurement of J/ψ polarization in pp collisions at [Formula: see text].

An angular analysis of the decay J/ψ→µ+µ- is performed to measure the polarization of prompt J/ψ mesons produced in pp collisions at [Formula: see text]. The dataset corresponds to an integrated luminosity of 0.37 fb-1 collected with the LHCb detector. The measurement is presented as a function of transverse momentum, pT, and rapidity, y, of the J/ψ meson, in the kinematic region 2

Measurement of the forward energy flow in pp collisions at [Formula: see text].

The energy flow created in pp collisions at [Formula: see text] is studied within the pseudorapidity range 1.9<η<4.9 with data collected by the LHCb experiment. The measurements are performed for inclusive minimum-bias interactions, hard scattering processes and events with an enhanced or suppressed diffractive contribution. The results are compared to predictions given by Pythia-based and cosmic-ray event generators, which provide different models of soft hadronic interactions.

Measurements of the branching fractions of [Formula: see text] decays.

The branching fractions of the decay [Formula: see text] for different intermediate states are measured using data, corresponding to an integrated luminosity of 1.0 fb-1, collected by the LHCb experiment. The total branching fraction, its charmless component [Formula: see text] and the branching fractions via the resonant [Formula: see text] states ηc (1S) and ψ(2S) relative to the decay via a J/ψ intermediate state are [Formula: see text] Upper limits on the B+ branching fractions into the ηc (2S) meson and into the charmonium-like states X(3872) and X(3915) are also obtained.

Observation of excited Λ(b)(0) baryons.

Using pp collision data corresponding to 1.0 fb(-1) integrated luminosity collected by the LHCb detector, two narrow states are observed in the Λ(b)(0)π(+)π(-) spectrum with masses 5911.97±0.12(stat)±0.02(syst)±0.66(Λ(b)(0) mass) MeV/c(2) and 5919.77±0.08(stat)±0.02(syst)±0.66(Λ(b)(0) mass) MeV/c(2). The significances of the observations are 5.2 and 10.2 standard deviations, respectively. These states are interpreted as the orbitally excited Λ(b)(0) baryons, Λ(b)(*0)(5912) and Λ(b)(*0)(5920).

Measurement of the B¯(s)(0) effective lifetime in the J/ψf0(980) final state.

The effective lifetime of the B ¯(s)(0) meson in the decay mode B¯(s)(0)→J/ψf(0)(980) is measured using 1.0 fb(-1) of data collected in pp collisions at √s=7 TeV with the LHCb detector. The result is 1.700±0.040±0.026 ps, where the first uncertainty is statistical and the second systematic. As the final state is CP-odd, and CP violation in this mode is measured to be small, the lifetime measurement can be translated into a measurement of the decay width of the heavy B¯(s)(0) mass eigenstate, Γ(H)=0.588±0.014±0.009 ps(-1).

Observation of B0→D¯(0)K(+)K(-) and evidence for B(s)(0)→D¯(0)K(+)K(-).

The first observation of the decay B0→D¯(0)K(+)K(-) is reported from an analysis of 0.62 fb(-1) of pp collision data collected with the LHCb detector. Its branching fraction is measured relative to that of the topologically similar decay B(0)→D ¯(0)π(+)π(-) to be (B(B(0)→D¯(0)K(+)K(-))/B(B(0)→D¯(0)π(+)π(-))=0.056±0.011±0.007,where the first uncertainty is statistical and the second is systematic. The significance of the signal is 5.8σ. Evidence, with 3.8σ significance, for B(s)(0)→D¯(0)K(+)K(-) decays is also presented. The relative branching fraction is measured to be B(B(s)(0)→D¯(0)K(+)K(-))/B(B(0)→D¯(0)K(+)K(-))=0.90±0.27±0.20. These channels are of interest to study the mechanisms behind hadronic B decays, and open new possibilities for CP violation analyses with larger data sets.

First evidence of direct CP violation in charmless two-body decays of Bs0 mesons.

Using a data sample corresponding to an integrated luminosity of 0.35 fb-1 collected by LHCb in 2011, we report the first evidence of CP violation in the decays of Bs0} mesons to K±π∓ pairs, ACP(Bs0→Kπ)=0.27±0.08(stat)±0.02(syst), with a significance of 3.3σ. Furthermore, we report the most precise measurement of CP violation in the decays of B0 mesons to K±π∓ pairs, ACP(B0→Kπ)=-0.088±0.011(stat)±0.008(syst), with a significance exceeding 6σ.

Strong constraints on the rare decays B(s)(0) → µ+ µ- and B0 → µ+ µ-.

A search for B(s)(0) → µ+ µ- and B0 → µ+ µ decays is performed using 1.0 fb(-1) of pp collision data collected at sqrt[s] = 7 TeV with the LHCb experiment at the Large Hadron Collider. For both decays, the number of observed events is consistent with expectation from background and standard model signal predictions. Upper limits on the branching fractions are determined to be B(B(s)(0) → µ+ µ-) < 4.5(3.8)×10(-9) and B(B0 → µ+ µ-) < 1.0(0.81)×10(-9) at 95% (90%) confidence level.

Determination of the sign of the decay width difference in the B(s)(0) system.

The interference between the K+ K- S-wave and P-wave amplitudes in B(s)(0) → J/ψK+ K- decays with the K+ K- pairs in the region around the ϕ(1020) resonance is used to determine the variation of the difference of the strong phase between these amplitudes as a function of K+ K- invariant mass. Combined with the results from our CP asymmetry measurement in B(s)(0) → J/ψϕ decays, we conclude that the B(s)(0) mass eigenstate that is almost CP = +1 is lighter and decays faster than the mass eigenstate that is almost CP = -1. This determines the sign of the decay width difference ΔΓ(s) ≡ Γ(L) - Γ(H) to be positive. Our result also resolves the ambiguity in the past measurements of the CP violating phase ϕ(s) to be close to zero rather than π. These conclusions are in agreement with the standard model expectations.