72 research outputs found
The correlation between auditory speech sensitivity and speaker recognition ability
Fonologische representatie
Kondo effect in a Luttinger liquid: nonuniversality of the Wilson ratio
Using a precise coset Ising-Bose representation, we show how backscattering
of electrons off a magnetic impurity destabilizes the two-channel Kondo fixed
point and drives the system to a new fixed point, in agreement with previous
results. In addition, we verify the scaling proposed by Furusaki and Nagaosa
and prove that the other possible critical fixed point, namely the local Fermi
liquid class, is not completely universal when backscattering is included
because the Wilson ratio is not well-defined in the spinon basis.Comment: 4 pages, RevTeX; to appear in Physical Review
A high stability semiconductor laser system for a Sr-based optical lattice clock
We describe a frequency stabilized diode laser at 698 nm used for high
resolution spectroscopy of the 1S0-3P0 strontium clock transition. For the
laser stabilization we use state-of-the-art symmetrically suspended optical
cavities optimized for very low thermal noise at room temperature. Two-stage
frequency stabilization to high finesse optical cavities results in measured
laser frequency noise about a factor of three above the cavity thermal noise
between 2 Hz and 11 Hz. With this system, we demonstrate high resolution remote
spectroscopy on the 88Sr clock transition by transferring the laser output over
a phase-noise-compensated 200 m-long fiber link between two separated
laboratories. Our dedicated fiber link ensures a transfer of the optical
carrier with frequency stability of 7 \cdot 10^{-18} after 100 s integration
time, which could enable the observation of the strontium clock transition with
an atomic Q of 10^{14}. Furthermore, with an eye towards the development of
transportable optical clocks, we investigate how the complete laser system
(laser+optics+cavity) can be influenced by environmental disturbances in terms
of both short- and long-term frequency stability.Comment: 9 pages, 9 figures, submitted to Appl. Phys.
Polarised quark distributions in the nucleon from semi-inclusive spin asymmetries
We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1~GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10~GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 1 GeV. Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at =10 GeV. The polarised valence quark distribution, , is positive and the polarisation increases with . The polarised valence quark distribution, , is negative and the non-strange sea distribution, , is consistent with zero over the measured range of . We find for the first moments , and , where we assumed . We also determine for the first time the second moments of the valence distributions .We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.0031 GeV 2 . Compared to our previous publication on this subject, with the new data the statistical errors have been reduced by nearly a factor of two. From these asymmetries and our inclusive spin asymmetries we determine the polarised quark distributions of valence quarks and non-strange sea quarks at Q 2 =10 GeV 2 . The polarised u valence quark distribution, Δu v ( x ), is positive and the polarisation increases with x . The polarised d valence quark distribution, Δd v ( x ), is negative and the non-strange sea distribution, Δ q ̄ (x) , is consistent with zero over the measured range of x . We find for the first moments ∫ 0 1 Δu v (x) d x=0.77±0.10±0.08 , ∫ 0 1 Δd v (x) d x=−0.52±0.14±0.09 and ∫ 0 1 Δ q ̄ (x) d x=0.01±0.04±0.03 , where we assumed Δ u ̄ (x)=Δ d ̄ (x) . We also determine for the first time the second moments of the valence distributions ∫ 0 1 xΔq v (x) d x
Prompt K_short production in pp collisions at sqrt(s)=0.9 TeV
The production of K_short mesons in pp collisions at a centre-of-mass energy
of 0.9 TeV is studied with the LHCb detector at the Large Hadron Collider. The
luminosity of the analysed sample is determined using a novel technique,
involving measurements of the beam currents, sizes and positions, and is found
to be 6.8 +/- 1.0 microbarn^-1. The differential prompt K_short production
cross-section is measured as a function of the K_short transverse momentum and
rapidity in the region 0 < pT < 1.6 GeV/c and 2.5 < y < 4.0. The data are found
to be in reasonable agreement with previous measurements and generator
expectations.Comment: 6+18 pages, 6 figures, updated author lis
Roentgenographische Texturuntersuchungen an feinkoernigen Sedimenten unterschiedlicher Kompaktion
SIGLETIB: RO 786 (4) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
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