Upgrades to the LHCb computing infrastructure in the first long shutdown of the LHC have allowed for high quality decay information to be calculated by the software trigger making a separate offline ...event reconstruction unnecessary. Furthermore, the storage space of the triggered candidate is an order of magnitude smaller than the entire raw event that would otherwise need to be persisted. Tesla is an application designed to process the information calculated by the trigger, with the resulting output used to directly perform physics measurements.
Most adults, especially women, hold infants and objects representing infants, such as dolls, preferentially on the left side. The attention hypothesis credits the effect to left-directed attention ...for perception of emotionally salient targets, faces being prime examples. Support comes from studies showing stronger left visual hemispace (LVH) biases in left-holders than right-holders on the Chimeric Faces Test (CFT), but control tests with non-social/emotional objects are needed. We therefore observed young women holding a doll, a book, and a bag, and compared their scores with their performance on the CFT. We also assessed their handedness to check on its possible role. Overall, only the doll elicited a significant side bias, with 57% of all holds on the left, 2% in the middle, and 41% on the right. On the CFT, only left-holders had an LVH bias, whereas right-holders had no bias in either direction. Only the doll-hold scores were consistently related to CFT scores, and for none of the objects was handedness related to side-of-hold.
The branching fraction of the rare decay Lambda(0 )(b)-> Lambda(1520)mu(+)mu(-) is measured for the first time, in the squared dimuon mass intervals q(2), excluding the J/psi and psi(2S) regions. ...The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb(-1). The result in the highest q(2) interval, q(2) > 15.0 GeV2/c(4), where theoretical predictions have the smallest model dependence, agrees with the predictions.
The decay B- -> Lambda(+)(c)(Lambda) over bar K--(c)- is studied in proton-proton collisions at a center-of-mass energy of root s = 13 TeV using data corresponding to an integrated luminosity of 5 ...fb(-1) collected by the LHCb experiment. In the Lambda K-+(c)- system, the Xi(c)(2930)(0) state observed at the BABAR and Belle experiments is resolved into two narrower states, Xi(c)(2923)(0) and Xi(c)(2939)(0), whose masses and widths are measured to be m(Xi(c)(2930)(0) = 2924.5 +/- 0.4 +/- 1.1 Mev, m Xi(c)(2930)(0)) = 2938.5 +/- 0.9 +/- 2.3 Mev, Gamma(Xi(c)(2930)(0)) = 4.8 +/- 0.9 +/- 1.5 MeV, Gamma(Xi(c)(2930)(0) - 11.0 +/- 1.9 +/- 7.5 MeV, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Lambda K-+(c)- sample. Evidence of a new Xi(c)(2930)(0) state is found with a local significance of 3.8 sigma, whose mass and width are measured to be 2881.8 +/- 3.1 +/- 8.5 MeV and 12.4 +/- 5.3 +/- 5.8 MeV, respectively. In addition, evidence of a new decay mode Xi(c)(2930)(0) -> Lambda K-+(c) is found with a significance of 3.7 sigma. The relative branching fraction of B- -> Lambda(+)(c)(Lambda) over bar K--(c)- with respect to the B- -> D+D-K- decay is measured to be 2.36 +/- 0.11 +/- 0.22 +/- 0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.
A study of the B+ -> (KSK+)-K-0 K-pi(+) and B+ -> (KSK+K+)-K-0 pi(-) decays is performed using proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV at the LHCb experiment. The ...(KSK)-K-0 pi invariant mass spectra from both decay modes reveal a rich content of charmonium resonances. New precise measurements of the eta(c) and eta(c)(2S) resonance parameters are performed and branching fraction measurements are obtained for B+ decays to eta(c), J/psi, eta(c)(2S) and chi(c1) resonances. In particular, the first observation and branching fraction measurement of B+ -> chi K-c0(0)pi(+) is reported as well as first measurements of the B+ -> (KK+K-)-K-0 pi(+) and B+ -> (KK+K+)-K-0 pi(-) branching fractions. Dalitz plot analyses of eta(c) -> (KSK)-K-0 pi and eta(c)(2S) -> (KSK)-K-0 pi decays are performed. A new measurement of the amplitude and phase of the K pi S-wave as functions of the K pi mass is performed, together with measurements of the K-0*(1430), K-0*(1950) and a(0)(1700) parameters. Finally, the branching fractions of chi(c1) decays to K* resonances are also measured.
A measurement of charm mixing and CP-violating parameters is reported, using B over bar -> D0(-> K0S pi+pi-)x mu- nu over bar mu X decays reconstructed in proton-proton collisions collected by ...the LHCb experiment during the years 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb-1. The measured mixing and CP-violating parameters are xCP = 4.29 1 1.48(stat) 1 0.26(syst) x 10-3, yCP = 12.61 1 3.12(stat) 1 0.83(syst) x 10-3, Ax = -0.77 1 0.93(stat) 1 0.28(syst) x 10-3, Ay = 3.01 1 1.92(stat) 1 0.26(syst) x 10-3. The results are complementary to and consistent with previous measurements. A combination with the recent LHCb analysis of D*+ -> D0(-> K0S pi+ pi-)pi+ decays is reported.
Photographic and direct-observation studies show that most adults hold infants on the left side. This basic directional effect is well established, but other details are still uncorroborated, ...uncertain, or inconsistent across studies. These include the overall strength of the bias, the role of the sex, parental status, and experience of the holder, and the sex and age of the infant. Given their importance for understanding the bias, we sought further information from a large sample of photographs of mothers and fathers, some of them first-time parents, others not, holding their infants in the first minutes, hours, or days after birth. The results confirmed the basic directional effect and provided information on the other variables. They also raise questions for further research, especially as it pertains to the use of photographs vs direct observation.
The interpretation of cosmic antiproton flux measurements from space-borne experiments is currently limited by the knowledge of the antiproton production cross-section in collisions between primary ...cosmic rays and the interstellar medium. Using collisions of protons with an energy of 6.5 TeV incident on helium nuclei at rest in the proximity of the interaction region of the LHCb experiment, the ratio of antiprotons originating from antihyperon decays to prompt production is measured for antiproton momenta between 12 and 110 GeV/c. The dominant antihyperon contribution, namely (Lambda) over bar -> (p) over bar pi(+) decays from promptly produced (Lambda) over bar particles, is also exclusively measured. The results complement the measurement of prompt antiproton production obtained from the same data sample. At the energy scale of this measurement, the antihyperon contributions to antiproton production are observed to be significantly larger than predictions of commonly used hadronic production models.
Most women hold infants on their left side. They do the same when depicted in works of art. Does the latter accurately reflect the real-life bias, the artist's own aesthetic preference, or something ...else, such as the artist's handedness, sex, direction of attentional bias, or even the artist's own side-preference for holding infants? As a first step to finding out, we showed 272 young adults (85 men, 187 women) 20 pairs of paintings of the Madonna and Child, the original on one side, its mirror-reversal on the other, and asked which one they preferred. Along with assessing the effects of the variables already mentioned, we used equal numbers of paintings originally depicting left-holds and right-holds to control for the possible effects of differences between the paintings other than side-of-hold itself, such as in their colour scheme, background details, and the type of hold shown (e.g., cradle vs seated on lap). Each pair was presented twice, once with the original on the left, once on the right, for a total of 40 trials. Women and men alike more often preferred left-hold images, but the difference was significant only for women. Preferences were also stronger for original left-hold paintings than for the mirror-reversals of original right-hold paintings, suggesting that the originals differed in ways affecting preference beyond those we tried to control. Overall preference for left-hold images was enhanced when the images were on the viewer's left. As for the other variables, they were for the most part unrelated to preferences. The reasons for the preference thus remain unclear but it is evidently affected by multiple variables, with at least some clearly different from those affecting side-of-hold preferences of real mothers holding real infants.
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