Results on mixing in the D0 system from BaBar

With 12.3 fb-1 collected by the BaBar experiment in 2001, the mixing parameter y = Delta(Gamma)/(2 Gamma) is determined from the ratio of the D0 lifetimes measured in the D0 --> K- pi+ and in the D0 --> K- K+ decay modes. The preliminary result y = (-1.0 +- 2.2(stat.) +- 1.7(syst.))% is obtained. Also presented is the status of measuring the mixing parameters y and x^2 = [Delta(M)/Gamma]^2 from a simultaneous fit to the time evolution of the decay time distributions of Cabibbo-favored right-sign (D0 --> K- pi+) and doubly Cabibbo-suppressed wrong-sign (D0 --> K+ pi-) decays. The wrong-sign decay rate, R_WS = (# WS decays)/(# RS decays) = (0.38 +- 0.04(stat.) +- 0.02(syst.))% is obtained from the fit to 23 fb-1 of BaBar data taken in 2000.Comment: 9 pages, 3 postscript figures, contribution to the proceedings of the 9th International Symposium on Heavy Flavour Physics, September 2001, Pasadena, US

Forward Proton Detectors at High Luminosity at the LHC

We discuss the special challenges posed by measuring diffractive and forward physics at the LHC at high luminosity and the solutions proposed by the FP420 R&D collaboration.Comment: 5 pages, no pictures, contribution to the proceedings of ICHEP0

Forward physics with CMS

Forward physics with CMS at the LHC covers a wide range of physics subjects, including very low-x_Bj QCD, underlying event and multiple interactions characteristics, gamma-mediated processes, shower development at the energy scale of primary cosmic ray interactions with the atmosphere, diffraction in the presence of a hard scale and even MSSM Higgs discovery in central exclusive production. Selected feasibility studies to illustrate the forward physics potential of CMS are presented.Comment: Talk on behalf of CMS presented at 2008 Physics at LHC conference, Split, Croatia, Sept 29 - Oct 4 200

Interaction of excitation and inhibition in processing of pure tone and amplitude-modulated stimuli in the medial superior olive of the mustached bat

1. In mammals with good low-frequency hearing, the medial superior olive (MSO) processes interaural time or phase differences that are important cues for sound localization. Its cells receive excitatory projections from both cochlear nuclei and are thought to function as coincidence detectors. The response patterns of MSO neurons in most mammals are predominantly sustained. In contrast, the MSO in the mustached bat is a monaural nucleus containing neurons with phasic discharge patterns. These neurons receive projections from the contralateral anteroventral cochlear nucleus (AVCN) and the ipsilateral medial nucleus of the trapezoid body (MNTB). 2. To further investigate the role of the MSO in the bat, the responses of 252 single units in the MSO to pure tones and sinusoidal amplitude-modulated (SAM) stimuli were recorded. The results confirmed that the MSO in the mustached bat is tonotopically organized, with low frequencies in the dorsal part and high frequencies in the ventral part. The 61-kHz region is overrepresented. Most neurons tested (88%) were monaural and discharged only in response to contralateral stimuli. Their response could not be influenced by stimulation of the ipsilateral ear. 3. Only 11% of all MSO neurons were spontaneously active. In these neurons the spontaneous discharge rate was suppressed during the stimulus presentation. 4. The majority of cells (85%) responded with a phasic discharge pattern. About one-half (51%) responded with a level-independent phasic ON response. Other phasic response patterns included phasic OFF or phasic ON-OFF, depending on the stimulus frequency. Neurons with ON-OFF discharge patterns were most common in the 61-kHz region and absent in the high-frequency region. 5. Double tone experiments showed that at short intertone intervals the ON response to the second stimulus or the OFF response to the first stimulus was inhibited. 6. In neuropharmacological experiments, glycine applied to MSO neurons (n = 71) inhibited any tone-evoked response. In the presence of the glycine antagonist strychnine the response patterns changed from phasic to sustained (n = 35) and the neurons responded to both tones presented in double tone experiments independent of the intertone interval (n = 5). The effects of strychnine were reversible. 7. Twenty of 21 neurons tested with sinusoidally amplitude-modulated (SAM) signals exhibited low-pass or band-pass filter characteristics. Tests with SAM signals also revealed a weak temporal summation of inhibition in 13 of the 21 cells tested.(ABSTRACT TRUNCATED AT 400 WORDS) </jats:p

Mixing in the D0 system - Results from collider experiments

Mixing in the D0 system may provide a sensitive probe for new physics beyond the Standard Model (SM) but has so far eluded experimental observation. The SM predictions are typically small (< 10^{-3}) for the mixing parameters x, y which, in the absence of charge-parity (CP) symmetry violation, measure the mass (x= Delta(m)/Gamma) and lifetime (y= Delta(Gamma)/2Gamma) difference of the CP eigenstates in the D0 system. The asymmetric B-factory experiments BABAR and Belle open up the opportunity of measuring x, y with unprecedented statistical precision and sample purities. Results from BABAR and Belle, and from CLEO are reviewed.Comment: 28 pages, 7 figures, typos correcte

Synaptic Inhibition Influences the Temporal Coding Properties of Medial Superior Olivary Neurons. An in vitro Study

The medial superior olive (MSO) functions as a coincidence detector for interaural time and phase differences by integrating excitatory synaptic inputs. Recent studies demonstrating glycinergic projections to MSO neurons suggest that coincidence detection results from the temporal integration of both EPSPs and IPSPs. We examined the impact of synaptic inhibition on the temporal coding properties of gerbil MSO neurons in vitro with intracellular recordings and electrical stimulation. For low-level bilateral electric stimulation, the EPSPs summated to produce an action potential in 73% of MSO neurons if they occurred within 50–500 microseconds of one another. Synaptic inhibition became more prominent at higher stimulus amplitudes in 73% of MSO neurons, and could block an evoked action potential if the stimuli to each pathway were delivered within 250 microseconds of one another. The glycine receptor antagonist strychnine influenced the response to simulated interaural time differences. In the presence of strychnine, interstimulus delays that originally resulted in full action potential suppression were sufficient to evoke an action potential. For trains of stimuli, as stimulus intensity increased (spatial summation), or as stimulus repetition rate increased to 100–500 Hz (temporal summation), there was a decrease in the number of stimulus pulses that evoked an action potential. In the presence of strychnine, MSO neurons generated a greater percentage of action potentials to the stimulus trains. When stimulus trains were delivered bilaterally, MSO neurons fired a greater number of action potentials at specific interstimulus time differences, and were selectively inhibited at other time differences.(ABSTRACT TRUNCATED AT 250 WORDS)</jats:p

Sensitivity to interaural time differences in the medial superior olive of a small mammal, the Mexican free-tailed bat

Neurons in the medial superior olive (MSO) are thought to encode interaural time differences (ITDs), the main binaural cues used for localizing low-frequency sounds in the horizontal plane. The underlying mechanism is supposed to rely on a coincidence of excitatory inputs from the two ears that are phase-locked to either the stimulus frequency or the stimulus envelope. Extracellular recordings from MSO neurons in several mammals conform with this theory. However, there are two aspects that remain puzzling. The first concerns the role of the MSO in small mammals that have relatively poor low-frequency hearing and whose heads generate only very small ITDs. The second puzzling aspect of the scenario concerns the role of the prominent binaural inhibitory inputs to MSO neurons. We examined these two unresolved issues by recording from MSO cells in the Mexican free-tailed bat. Using sinusoidally amplitude-modulated tones, we found that the ITD sensitivities of many MSO cells in the bat were remarkably similar to those reported for larger mammals. Our data also indicate an important role for inhibition in sharpening ITD sensitivity and increasing the dynamic range of ITD functions. A simple model of ITD coding based on the timing of multiple inputs is proposed. Additionally, our data suggest that ITD coding is a by-product of a neuronal circuit that processes the temporal structure of sounds. Because of the free-tailed bat's small head size, ITD coding is most likely not the major function of the MSO in this small mammal and probably other small mammals

Spatial Dependence in Wind and Optimal Wind Power Allocation: A Copula Based Analysis

The investment decision on the placement of wind turbines is, neglecting legal formalities, mainly driven by the aim to maximize the expected annual energy production of single turbines. The result is a concentration of wind farms at locations with high average wind speed. While this strategy may be optimal for single investors maximizing their own return on investment, the resulting overall allocation of wind turbines may be unfavorable for energy suppliers and the economy because of large fluctuations in the overall wind power output. This paper investigates to what extent optimal allocation of wind farms in Germany can reduce these fluctuations. We analyze stochastic dependencies of wind speed for a large data set of German on- and offshore weather stations and find that these dependencies turn out to be highly nonlinear but constant over time. Using copula theory we determine the value at risk of energy production for given allocation sets of wind farms and derive optimal allocation plans. We find that the optimized allocation of wind farms may substantially stabilize the overall wind energy supply on daily as well as hourly frequency.Wind power; Vine copula; Optimal turbine allocation