Exploring attention in vr:Effects of visual and auditory modalities

Attention requires the ability to stay concentrated and alert to stimuli over prolonged periods of time. Virtual reality (VR) can be used in various training situations where attention plays a major role (e.g. system operators). Here, we investigate the effects of visual and auditory stimuli on attention performance in a VR aquarium (Nesplora Aquarium). Participants pay attention to the main fish tank and respond by pressing a button. The stimuli are different species of fish that are delivered either via visual or auditory channels. Thirty-seven participants completed the VR test and paper questionnaires. We found that attention is influenced differently by sensory modalities. Attention performance measured by the reaction time to correct targets and the number of errors of omission were better in the visual condition, while the number of errors of commission were lower in the auditory condition. The human factors’ role in attention tasks is also discussed.</p

Roadmap for selected key measurements of LHCb

379 pagesSix of the key physics measurements that will be made by the LHCb experiment, concerning CP asymmetries and rare B decays, are discussed in detail. The "road map" towards the precision measurements is presented, including the use of control channels and other techniques to understand the performance of the detector with the first data from the LHC

Measurements of the Branching fractions for B_(s) -> D_(s)πππ and Λ_b^0 -> Λ_c^+πππ

Branching fractions of the decays $H_b\to H_c\pi^-\pi^+\pi^-$ relative to $H_b\to H_c\pi^-$ are presented, where $H_b$ ($H_c$) represents B^0-bar($D^+$), $B^-$ ($D^0$), B_s^0-bar ($D_s^+$) and $\Lambda_b^0$ ($\Lambda_c^+$). The measurements are performed with the LHCb detector using 35${\rm pb^{-1}}$ of data collected at $\sqrt{s}=7$ TeV. The ratios of branching fractions are measured to be B(B^0-bar -&gt; D^+\pi^-\pi^+\pi^-)/ B(B^0-bar -&gt; D^+\pi^-) = 2.38\pm0.11\pm0.21 B(B^- -&gt; D^0\pi^-\pi^+\pi^-) / B(B^- -&gt; D^0\pi^-) = 1.27\pm0.06\pm0.11 B(B_s^0-bar -&gt; D_s^+\pi^-\pi^+\pi^-) / B(B_s^0-bar -&gt; D_s^+\pi^-) = 2.01\pm0.37\pm0.20 B(\Lambda_b^0-&gt;\Lambda_c^+\pi^-\pi^+\pi^-) / B(\Lambda_b^0 -&gt; \Lambda_c^+\pi^-) = 1.43\pm0.16\pm0.13. 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

Search for CP violation in D+ -> K- K+ pi(+) decays

A model-independent search for direct CP violation in the Cabibbo-suppressed decay D+ -> K- K+ pi(+) in a sample of approximately 370 000 decays is carried out. The data were collected by the LHCb experiment in 2010 and correspond to an integrated luminosity of 35 pb(-1). The normalized Dalitz plot distributions for D+ and D- are compared using four different binning schemes that are sensitive to different manifestations of CP violation. No evidence for CP asymmetry is found

Determination of f(s)/f(d) for 7 TeV pp collisions and measurement of the B0→D-K+ branching fraction.

The relative abundance of the three decay modes B(0)→D(-)K(+), B(0)→D(-)π(+), and B(s)(0)→D(s)(-)π(+) produced in 7 TeV pp collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb(-1). The branching fraction of B(0)→D(-)K(+) is found to be B(B(0)→D(-)K(+)) = (2.01 ± 0.18(stat) ± 0.14(syst)) × 10(-4). The ratio of fragmentation fractions f(s)/f(d) is determined through the relative abundance of B(s)(0)→D(s)(-)π(+) to B(0)→D(-)K(+) and B(0)→D(-)π(+), leading to f(s)/f(d) = 0.253 ± 0.017 ± 0.017 ± 0.020, where the uncertainties are statistical, systematic, and theoretical, respectively

First observation of Bs -&gt; J/psi f0(980) decays

Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the hadronic decay Bs -&gt; J/psi f0(980) is observed. This CP eigenstate mode could be used to measure mixing-induced CP violation in the B_s system. Using a fit to the pi+ pi- mass spectrum with interfering resonances gives R_{f0/phi} = [Gamma(Bs -&gt; J/psi f0, f0 -&gt; pi+ pi-)]/[Gamma(Bs -&gt; J/psi phi, phi -&gt; K+K-)] = 0.252^{+0.046+0.027}_{-0.032-0.033}, where the uncertainties are statistical and systematic, respectively

Determination of f_s/f_d for 7 TeV pp collisions and a measurement of the branching fraction of the decay Bd-&gt;D-K+

The relative abundance of the three decay modes $B_d \to D^- K^+$, $B_d \to D^- \pi^+$ and $B_s \to D_s^- \pi^+$ produced in 7 TeV $pp$ collisions at the LHC is determined from data corresponding to an integrated luminosity of 35 pb$^{-1}$. The branching fraction of $B_d \to D^- K^+$ is found to be $\cal B (B_d \to D^- K^+) = (2.01 \pm 0.18^{\textrm{stat}} \pm 0.14^{\textrm{syst}})\times 10^{-4}$. The ratio of fragmentation fractions \fsfdt is determined through the relative abundance of $B_s \to D_s^- \pi^+$ to $B_d \to D^- K^+$ and $B_d \to D^-\pi^+$, leading to $f_s/f_d = 0.253 \pm 0.017 \pm 0.017 \pm 0.020$, where the uncertainties are statistical, systematic, and theoretical respectively

Search for the rare decays Bs --&gt;mumu and Bd --&gt;mumu

A search for the decays Bs--&gt;mumu and Bd--&gt;mumu is performed with about 37 pb^{-1} of pp collisions at sqrt{s} = 7 TeV collected by the LHCb experiment at the Large Hadron Collider at CERN. The observed numbers of events are consistent with the background expectations. The resulting upper limits on the branching ratios are BR(Bs--&gt;mumu) &lt; 5.6 x 10^{-8} and BR(Bd--&gt;mumu) &lt;1.5 x 10^{-8} at 95% confidence level

First Observation of the Decays (B)over-bar(0) -> D+K-pi(+)pi(-) and B- -> (DK-)-K-0 pi(+)pi(-)

First observations of the Cabibbo-suppressed decays (B) over bar (0) -> D+K-pi(+)pi(-) and B- -> (DK-)-K-0 pi(+)pi(-) are reported using 35 pb(-1) of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo-favored decays, from which we obtain B((B) over bar (0) -> D+K-pi(+)pi(-))/B((B) over bar (0) -> D+pi(-)pi(+)pi(-) = (5.9 +/- 1.1 +/- 0.5) x 10(-2) and B(B- -> (DK-)-K-0 pi(+)pi(-))/B(B- -> D-0 pi(-)pi(+)pi(-)) = (0.9 +/- 1.3 +/- 0.9) x 10(-2), where the uncertainties are statistical and systematic, respectively. The B- -> (DK-)-K-0 pi(+)pi(-) decay is particularly interesting, as it can be used in a similar way to B- -> (DK-)-K-0 to measure the Cabibbo-Kobayashi-Maskawa phase gamma

Absolute luminosity measurements with the LHCb detector at the LHC

Absolute luminosity measurements are of general interest for colliding-beam experiments at storage rings. These measurements are necessary to determine the absolute cross-sections of reaction processes and are valuable to quantify the performance of the accelerator. Using data taken in 2010, LHCb has applied two methods to determine the absolute scale of its luminosity measurements for proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV . In addition to the classic “van der Meer scan” method a novel technique has been developed which makes use of direct imaging of the individual beams using beam-gas and beam-beam interactions.This beam imaging method is made possible by the high resolution of the LHCb vertex detector and the close proximity of the detector to the beams, and allows beam parameters such as positions, angles and widths to be determined. The results of the two methods have comparable precision and are in good agreement. Combining the two methods, an overal precision of 3.5% in the absolute luminosity determination is reached. The techniques used to transport the absolute luminosity calibration to the full 2010 data-taking period are presented