18557071
Measurement of “Pretzelosity” Asymmetry of Charged Pion Production in Semi-Inclusive Deep Inelastic Scattering on a Polarized 3 He Target
An experiment to measure single-spin asymmetries of semi-inclusive production of charged pions in deepinelastic
scattering on a transversely polarized 3He target was performed at Jefferson Laboratory in the kinematic
region of 0.16 <x< 0.35 and 1.4 < Q2 < 2.7 GeV2. Pretzelosity asymmetries on 3He, which are expressed as
the convolution of the h⊥
1T transverse-momentum-dependent distribution functions and the Collins fragmentation
functions in the leading order, were measured for the first time. Under the effective polarization approximation,
we extracted the corresponding neutron asymmetries from the measured 3He asymmetries and cross-section ratios
between the proton and 3He. Our results show that both π± on 3He and on neutron pretzelosity asymmetries are
consistent with zero within experimental uncertainties.
119223274
Short Range Correlations at Large xbj through Inclusive Electron-nucleus Scattering
The experiment, E08-014, in Hall-A at Jefferson Lab aims to study the short-range correlations (SRC) which are necessary to explain the nuclear strength absent in the mean field theory. The cross sections for $\mathrm{^{2}H}$, $\mathrm{^{3}He}$, $\mathrm{^{4}He}$, $\mathrm{^{12}C}$, $\mathrm{^{40}Ca}$ and $\mathrm{^{48}Ca}$, were measured via inclusive quasielastic electron scattering from these nuclei in a $\mathrm{Q^{2}}$ range between 0.8 and $\mathrm{2.8~(GeV/c)^{2}}$ for $x_{bj}>1$. The cross section ratios of heavy nuclei to $\mathrm{^{2}H}$ were extracted to study two-nucleon SRC for $1<x_{bj}<2$, while the study of three-nucleon SRC was carried out from the cross section ratios of heavy nuclei to $\mathrm{^{3}He}$ for $x_{bj}\ge 2$. Meanwhile, the isospin dependence in SRCs has also been examined through the cross section ratio of $\mathrm{^{48}Ca}$ and $\mathrm{^{40}Ca}$.
119255652
Bucking coil implementation on PMT for active canceling of magnetic field
Aerogel and water Cerenkov detectors were employed to tag kaons for a lambda hypernuclear spectroscopic experiment which used the (e,e'K{sup +}) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ~5 Gauss at the photomultiplier tubes (PMT) for these detectors which could not be easily shielded. As this field results in a lowered kaon detection efficiency, we implemented a bucking coil on each photomultiplier tubes to actively cancel this magnetic field, thus maximizing kaon detection efficiency.
121125876
Experimental design and simulation for the third generation (e, e-prime K+) hypernuclear spectroscopy at JLab
123612926
DAMA/LIBRA results and perspectives
The DAMA/LIBRA experiment, running at the Gran Sasso National Laboratory of the I.N.F.N. in Italy, has a sensitive mass of about 250 kg highly radiopure NaI(Tl). It is mainly devoted to the investigation of Dark Matter (DM) particles in the Galactic halo by exploiting the model independent DM annual modulation signature. The present DAMA/LIBRA experiment and the former DAMA/NaI one (the first generation experiment having an exposed mass of about 100 kg) have released so far results corresponding to a total exposure of 1.17 ton × yr over 13 annual cycles. They provide a model independent evidence of the presence of DM particles in the galactic halo at 8.9 � C.L.. A short summary of the obtained results is presented and future perspectives of the experiment mentioned.
55333370
The Annual Modulation Signature for Dark Matter: DAMA/LIBRA-Phase1 Results and Perspectives
The results obtained with the total exposure of 1.04 ton x yr collected by deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. during 7 annual cycles are summarized. The DAMA/LIBRA-phase1 and the former DAMA/NaI data (cumulative exposure 1.33 ton x yr, corresponding to 14 annual cycles) give evidence at 9.3 sigma C.L. for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radiopure NaI(Tl) target. The modulation amplitude of the single-hit events in the (2-6) keV energy interval is (0.0112 +/- 0.0012) cpd/kg/keV; the measured phase is (144 +/- 7) days and the measured period is (0.998 +/- 0.002) yr; values are in a good well in agreement with those expected for DM particles. No systematic or side reactions able to mimic the exploited DM signature have been found or suggested by anyone over more than a decade. Some of the perspectives of the presently running DAMA/LIBRA-phase2 are outlined.
121506888
Technical aspects in dark matter direct detection
In the field of dark matter direct detection, on the one hand, it is predicted by theoretical models that many dark matter candidates and scenarios are possible. On the other hand, a variety of detectors has been proposed, but most of them — by the fact — are still at R&D stage. Such a situation leads to some considerations on technical aspects on dark matter direct detection.