The B 0 a B A= 0 oscillation frequency I m d is measured by the LHCb experiment using a dataset corresponding to an integrated luminosity of 1.0 fb - 1 of protonaproton collisions at s = 7 TeV , and ...is found to be I m d = 0.5156 +/- 0.0051 (stat.) +/- 0.0033 (syst.) ps - 1 . The measurement is based on results from analyses of the decays B 0 a D - pi + (D - a K + pi - pi -) and B 0 a J / I K a 0 (J / I a mu + mu - , K a 0 a K + pi -) and their charge conjugated modes.
The asymmetry in the production cross-section I of D +/- mesons, A P = I (D +) - I (D -) I (D +) + I (D -) , is measured in bins of pseudorapidity IDT and transverse momentum p T within the ...acceptance of the LHCb detector. The result is obtained with a sample of D + a K S 0 pi + decays corresponding to an integrated luminosity of 1.0 fb-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 < p T < 18.0 GeV / c and 2.20 < IDT < 4.75 , the production asymmetry is A P = (- 0.96 +/- 0.26 +/- 0.18) % . The uncertainties quoted are statistical and systematic, respectively. The result assumes that any direct CP violation in the D + a K S 0 pi + decay is negligible. No significant dependence on IDT or p T is observed.
A binned Dalitz plot analysis of B +/- a D K +/- decays, with D a K S 0 pi + pi - and D a K S 0 K + K - , is performed to measure the CP-violating observables x +/- and y +/- which are sensitive to ...the CKM angle gamma. The analysis exploits 1.0 fb - 1 of data collected by the LHCb experiment. The study makes no model-based assumption on the variation of the strong phase of the D decay amplitude over the Dalitz plot, but uses measurements of this quantity from CLEO-c as input. The values of the parameters are found to be x - = (0.0 +/- 4.3 +/- 1.5 +/- 0.6) X 10 - 2 , y - = (2.7 +/- 5.2 +/- 0.8 +/- 2.3) X 10 - 2 , x + = (- 10.3 +/- 4.5 +/- 1.8 +/- 1.4) X 10 - 2 and y + = (- 0.9 +/- 3.7 +/- 0.8 +/- 3.0) X 10 - 2 . The first, second, and third uncertainties are the statistical, the experimental systematic, and the error associated with the precision of the strong-phase parameters measured at CLEO-c, respectively. These results correspond to gamma = (44 - 38 + 43) degree , with a second solution at gamma a gamma + 180 degree , and r B = 0.07 +/- 0.04 , where r B is the ratio between the suppressed and favoured B decay amplitudes.
Measurement of the effective lifetime Aaij, R; Abellan Beteta, C; Adametz, A ...
Physics letters. B,
10/2012, Volume:
716, Issue:
3-5
Journal Article
Peer reviewed
A precise determination of the effective B s 0 ? K + K - lifetime can be used to constrain contributions from physics beyond the Standard Model in the B s 0 meson system. Conventional approaches ...select B meson decay products that are significantly displaced from the B meson production vertex. As a consequence, B mesons with low decay times are suppressed, introducing a bias to the decay time spectrum which must be corrected. This analysis uses a technique that explicitly avoids a lifetime bias by using a neural network based trigger and event selection. Using 1.0 fb - 1 of data recorded by the LHCb experiment, the effective B s 0 ? K + K - lifetime is measured as 1.455 +/- 0.046 (stat.) +/- 0.006 (syst.) ps .
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1 of pp collision data collected by the LHCb ...experiment at a centre-of-mass energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x 10^{-5}. The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/- 0.9(syst.))%. Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The relative production rate of ... and B super(0) mesons is determined with the hadronic decays ... and B super(0) arrow ...right D super(-) K super(+). The measurement uses data corresponding to 1.0 fb super(-1) of pp collisions at a centre-of-mass energy of ... TeV recorded in the forward region with the LHCb experiment. The ratio of production rates, f sub( s) /f sub(d), is measured to be 0.238 plus or minus 0.004 plus or minus 0.015 plus or minus 0.021, where the first uncertainty is statistical, the second systematic, and the third theoretical. This is combined with a previous LHCb measurement to obtain f sub(s) /f sub(d)=0.256 plus or minus 0.020. The dependence of f sub(s) /f sub(d) on the transverse momentum and pseudorapidity of the B meson is determined using the decays ... and B super(0) arrow right D super(-) pi super(+). There is evidence for a decrease with increasing transverse momentum, whereas the ratio remains constant as a function of pseudorapidity. In addition, the ratio of branching fractions of the decays B super(0) arrow right D super(-) K super(+) and B super(0) arrow right D super(-) pi super(+) is measured to be 0.0822 plus or minus 0.0011 (stat) plus or minus 0.0025 (syst). Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The decay B super(0) arrow right DK super(*0) and the charge conjugate mode are studied using 1.0 fb super(-1) of pp ...collision data collected by the LHCb experiment at ... TeV in 2011. The CP asymmetry between the B super(0) arrow right DK super(*0) and the ... decay rates, with the neutral D meson in the CP-even final state K super(+) K super(-), is found to be ...where the first uncertainty is statistical and the second is systematic. In addition, favoured B super(0) arrow right DK super(*0) decays are reconstructed with the D meson in the non-CP eigenstate K super(+) pi super(-). The ratio of the B-flavour averaged decay rates in D decays to CP and non-CP eigenstates is measured to be ...where the ratio of the branching fractions of D super(0) arrow right K super(-) pi super(+) to D super(0) arrow right K super(+) K super(-) decays is included as multiplicative factor. The CP asymmetries measured with two control channels, the favoured B super(0) arrow right DK super(*0) decay with D arrow right K super(+) pi super(-) and the ... decay with D arrow right K super(+) K super(-), arealsoreported.Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).The angular distribution and differential branching fraction of the decay B super(+) arrow right K super(+) mu super(+) mu ...super(-) are studied with a dataset corresponding to 1.0fb super(-1) of integrated luminosity, collected by the LHCb experiment. The angular distribution is measured in bins of dimuon invariant mass squared and found to be consistent with Standard Model expectations. Integrating the differential branching fraction over the full dimuon invariant mass range yields a total branching fraction of ... (B super(+) arrow right K super(+) mu super(+) mu super(-)) = (4.36 plus or minus 0.15 plus or minus 0.18) 10 super(-7). These measurements are the most precise to date of the B super(+) arrow right K super(+) mu super(+) mu super(-) decay.Figure not available: see fulltext.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Figure not available: see fulltext. A measurement of the cross-section for pp arrow right Z arrow right e super(+)e ...super(-) is presented using data at ... TeV corresponding to an integrated luminosity of 0.94 fb super(-1). The process is measured within the kinematic acceptance p sub(T)>20 GeV/c and 2< eta <4.5 for the daughter electrons and dielectron invariant mass in the range 60-120 GeV/c super(2). The cross-section is determined to be ...where the first uncertainty is statistical, the second is systematic and the third is the uncertainty in the luminosity. The measurement is performed as a function of Z rapidity and as a function of an angular variable which is closely related to the Z transverse momentum. The results are compared with previous LHCb measurements and with theoretical predictions from QCD.
•Adsorption in affinity chromatography stationary phases reduces the pore diameter.•Accessibility and effective pore diffusion are depending on the pore diameter.•Diffusivity is obtained by fitting ...the general rate model to breakthrough curves.•A modified Ogston model describes pore diameter dependent diffusion coefficient.
The aim of this study is to model, describe and predict the mass transfer of IgG as a function of the agarose concentration in the protein A stationary phase, taking into account the influence of adsorption on the pore size. Therefore, particle size distribution, bed and bead porosities were examined by light microscopy, pressure-flow behavior and iSEC. Three agarose protein A stationary phases (2 wt%, 4 wt%, 6 wt%) were investigated. The pore size decreased from 116 nm for 2 wt% to 54 nm for 6 wt% and the porosity for the target molecule IgG was reduced by 25%. A shrinking core model approach was used to assess the influence of IgG adsorption on the pore size of the stationary phase and the diffusivity of IgG. Due to IgG adsorption, the pore diameter reduced by 24 nm, which is approximately two times its hydrodynamic diameter. Effective pore diffusivities of IgG were obtained by fitting the general rate model to breakthrough curves. They were in the range between 3.96·10−12m2/s and 6.5·10−12m2/s, decreasing as the agarose concentration increased. The DBC1% has a maximum for the 4 wt% agarose gel, showing optimal tradeoffs between accessibility, specific surface and diffusive mass transfer for IgG. A simple geometrical model was developed to describe the change in pore and filament diameters due to adsorption. The diffusion measured in protein A agarose beads can be described by a modification of the Ogston model. This enables the diffusion measured in protein A agarose networks to be predicted.
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