30,572 research outputs found
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ 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 s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=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 B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(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
Measurement of b-hadron masses
No full textMeasurements of b-hadron masses are performed with the exclusive decay modes B +→J/ψK +, B 0→J/ψK +, B0→J/ψKS0, Bs0→J/ψφ and Λb0→J/ψΛ using an integrated luminosity of 35pb -1 collected in pp collisions at a centre-of-mass energy of 7 TeV by the LHCb experiment. The momentum scale is calibrated with J/ψ→μ +μ - decays and verified to be known to a relative precision of 2 ×10 -4 using other two-body decays. The results are more precise than previous measurements, particularly in the case of the Bs0 and Λb0 masses
A critical discussion about optimisation approaches for ocean energy array design
No full textAs the technology readiness level of ocean energy devices moves from single units to small arrays, evidence from related industries suggests the need for integrated array design tools. Those tools implement all the functionality required for assessing the economic performance, technical reliability and environmental impact of the diverse subsystems to be accounted for in the design chain. These include device hydrodynamics, design of the electrical connection to shore, moorings and foundations design, as well as logistic requirements for the installation and maintenance of the farm. This paper presents a critical discussion of approaches for optimising the solutions of such a tool when the target of the problem is to achieve the lowest Levelised Cost of Energy (LCOE) solution. Firstly, the problem is formally described, pointing out the complexity of the architecture of the models, the intervening variables and the constraints and boundary conditions of the solution space. Then, approaches for identification of lowest LCOE solutions are examined, starting from simplified one-parameter sensitivity analyses-such as, for example, interdistance among devices, and distance to shore-to more complex heuristic approaches. All the above considerations will be illustrated through examples pertinent to the ocean energy sector
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Measurement of the B0–B0 oscillation frequency Δmd with the decays B0→D−π+ and B0→ J/ψK∗0
No full textThe B
0
–B
0
oscillation frequency Δmd is measured by the LHCb experiment using a dataset corresponding
to an integrated luminosity of 1.0 fb−1
of proton–proton collisions at √
s = 7 TeV, and is found to be
Δmd
=0.5156±0.0051 (stat.)±0.0033 (syst.) ps−1
. The measurement is based on results from analyses
of the decays B
0
→ D
−π
+ (D
−
→ K
+π
−π
−) and B
0
→ J/ψK
∗0
(J/ψ →μ
+μ
−,K
∗0
→ K
+π
−) and
their charge conjugated modes
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Search for exclusive b → u transitions in hadronic decays of B mesons involving Ds+ and Ds*+ mesons
No full textcomplete author list:
Alexander J.; Bebek C.; Berkelman K.; Bloom K.; Browder T.; Cassel D.; Cho H.; Coffman D.; Drell P.; Ehrlich R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Jones C.; Jones S.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Ng C.; Nordberg E.; Patterson J.; Peterson D.; Riley D.; Salman S.; Sapper M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Stephens R.; Yelton J.; Cinabro D.; Henderson S.; Kinoshita K.; Liu T.; Saulnier M.; Wilson R.; Yamamoto H.; Bergfeld T.; Eisenstein B.; Gollin G.; Ong B.; Palmer M.; Selen M.; Thaler J.; Sadoff A.; Ammar R.; Ball S.; Baringer P.; Bean A.; Besson D.; Coppage D.; Copty N.; Davis R.; Hancock N.; Kelly M.; Kwak N.; Lam H.; Kubota Y.; Lattery M.; Nelson J.; Patton S.; Perticone D.; Poling R.; Savinov V.; Schrenk S.; Wang R.; Alam M.; Kim I.; Nemati B.; O'Neill J.; Severini H.; Sun C.; Zoeller M.; Crawford G.; Daubenmier C.; Fulton R.; Fujino D.; Gan K.; Honscheid K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Morrow F.; Skovpen Y.; Sung M.; White C.; Butler F.; Fu X.; Kalbfleisch G.; Ross W.; Skubic P.; Snow J.; Wang P.; Wood M.; Brown D.; Fast J.; McIlwain R.; Miao T.; Miller D.; Modesitt M.; Payne D.; Shibata E.; Shipsey I.; Wang P.; Battle M.; Ernst J.; Kwon Y.; Roberts S.; Thorndike E.; Wang C.; Dominick J.; Lambrecht M.; Sanghera S.; Shelkov V.; Skwarnicki T.; Stroynowski R.; Volobouev I.; Wei G.; Zadorozhny P.; Artuso M.; He D.; Goldberg M.; Horwitz N.; Kennett R.; Mountain R.; Moneti G.; Muheim F.; Mukhin Y.; Playfer S.; Rozen Y.; Stone S.; Thulasidas M.; Vasseur G.; Zhu G.; Bartelt J.; Csorna S.; Egyed Z.; Jain V.; Akerib D.; Barish B.; Chadha M.; Chan S.; Cowen D.; Eigen G.; Miller J.; O'Grady C.; Urheim J.; Weinstein A.; Acosta D.; Athanas M.; Masek G.; Paar H.; Gronberg J.; Kutschke R.; Menary S.; Morrison R.; Nakanishi S.; Nelson H.; Nelson T.; Richman J.; Ryd A.; Tajima H.; Schmidt D.; Sperka D.; Witherell M.; Procario M.; Yang S.; Balest R.; Cho K.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Alexander J.P
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