5,473 research outputs found
Physical Reach of a Neutrino Factory in the 2+2 and 3+1 Four-Family Scenario
We compare the physical reach of a Neutrino Factory in the 2+2 and 3+1
four-family models, with similar results in the two schemes; in both cases huge
CP-violating effects can be observed with a near detector in the channel. We also study the capability of long baseline experiments
(optimized for the study of the three-family mixing parameter space) in
distinguishing a three (active) neutrino model from a four-family scenario.Comment: 5 latex2e pages, 2 figures; talk given at NuFact '01, Tsukuba, 24-30
May 200
The 2+2 and 3+1 Four-Family Neutrino Mixing at the Neutrino Factory
We upgrade the study of the physical reach of a Neutrino Factory in the Four
Family Neutrino Mixing scenario taking into account the latest LSND results
that points out how the 3+1 scheme cannot be completely ruled out within the
present experimental data (although the 2+2 scheme is still the preferred
choice when four neutrinos are considered). A detailed comparison of the
physical reach of the -factory in the two schemes is given, with similar
results for the sensitivity to the mixing angles. Huge CP-violating effects can
be observed in both schemes with a near, O(10) Km, detector of O(10) Kton size
in the channel. A smaller detector of 1 Kton size can
still observe very large effects in this channel.Comment: 38 Latex2e pages, 21 figures using epsfig, minor change
Two-zero Majorana textures in the light of the Planck results
The recent results of the Planck experiment put a stringent constraint on the
sum of the light neutrino masses, m1+m2+m3 < 0.23 eV (95 % CL). On the other
hand, two-zero Majorana mass matrix textures predict strong correlations among
the atmospheric angle and the sum of the masses. We use the Planck result to
show that, for the normal hierarchy case, the texture with vanishing (2,2) and
(3,3) elements is ruled out at a high confidence level; in addition, we
emphasize that a future measurement of the octant of the atmospheric mixing
angle (or the one sigma determination of it based on recent fit to neutrino
data) will put severe constraint on the possible structure of the Majorana mass
matrix. The implication of the above mentioned correlations for neutrinoless
double beta-decay are also discussed, for both normal and inverted orderings.Comment: 9 pages, 8 figure
A Theoretical Prediction of the Bs-Meson Lifetime Difference
We present the results of a quenched lattice calculation of the operator
matrix elements relevant for predicting the Bs width difference. Our main
result is (\Delta\Gamma_Bs/\Gamma_Bs)= (4.7 +/- 1.5 +/- 1.6) 10^(-2), obtained
from the ratio of matrix elements, R(m_b)=/<\bar
B_s^0|Q_L|B_s^0>=-0.93(3)^(+0.00)_(-0.01). R(m_b) was evaluated from the two
relevant B-parameters, B_S^{MSbar}(m_b)=0.86(2)^(+0.02)_(-0.03) and
B_Bs^{MSbar}(m_b) = 0.91(3)^(+0.00)_(-0.06), which we computed in our
simulation.Comment: 21 pages, 7 PostScript figure
Estimate of surface direct radiative forcing of desert dust from atmospheric modulation of the aerosol optical depth
Abstract. Measurements carried out on the island of Lampedusa, in the central Mediterranean, on 7 September 2005, show the occurrence of a quasi-periodic oscillation of aerosol optical depth, column water vapour, and surface irradiance in different spectral bands. The oscillation has a period of about 13 min and is attributed to the propagation of a gravity wave able to modify the vertical structure of the planetary boundary layer, as also confirmed by satellite images. The wave occurred during a Saharan dust event. The oscillation amplitude is about 0.1 for the aerosol optical depth, and about 0.4 cm for the column water vapour. The modulation of the downward surface irradiances is in opposition of phase with respect to aerosol optical depth and water vapour column variations. The perturbation of the downward irradiance produced by the aerosols is determined by comparing the measured irradiances with estimated irradiances at a fixed value of the aerosol optical depth, and by correcting for the effect of the water vapour in the shortwave spectral range. The direct radiative forcing efficiency, i.e., the radiative perturbation of the net surface irradiance produced by a unit of optical depth aerosol layer, is determined at different solar zenith angles as the slope of the irradiance perturbation versus the aerosol optical depth. The estimated direct surface forcing efficiency at about 60° solar zenith angle is â(181 ± 17) W mâ2 in the shortwave, and â(83 ± 7) W mâ2 in the photosynthetic spectral range. The estimated daily average forcing efficiencies are of about â79 and â46 W mâ2 for the shortwave and photosynthetic spectral range, respectively
Estimate of surface direct radiative forcing of desert dust from atmospheric modulation of the aerosol optical depth
Measurements carried out on the island of Lampedusa, in the central Mediterranean, on 7 September 2005, show the occurrence of a quasi-periodic oscillation of aerosol optical depth, column water vapour, and surface irradiance in different spectral bands. The oscillation has a period of about 13 min and is attributed to the propagation of a gravity wave able to modify the vertical structure of the planetary boundary layer, as also confirmed by satellite images. The wave occurred during a Saharan dust event. The oscillation amplitude is about 0.1 for the aerosol optical depth, and about 0.4 cm for the column water vapour. The modulation of the downward surface irradiances is in opposition of phase with respect to aerosol optical depth and water vapour column variations. The perturbation of the downward irradiance produced by the aerosols is determined by comparing the measured irradiances with estimated irradiances at a fixed value of the aerosol optical depth, and by correcting for the effect of the water vapour in the shortwave spectral range. The direct radiative forcing efficiency, i.e., the radiative perturbation of the net surface irradiance produced by a unit of optical depth aerosol layer, is determined at different solar zenith angles as the slope of the irradiance perturbation versus the aerosol optical depth. The estimated direct surface forcing efficiency at about 60° solar zenith angle is â(181 ± 17) W mâ2 in the shortwave, and â(83 ± 7) W mâ2 in the photosynthetic spectral range. The estimated daily average forcing efficiencies are of about â79 and â46 W mâ2 for the shortwave and photosynthetic spectral range, respectively
Probing new physics scenarios in accelerator and reactor neutrino experiments
We perform a detailed combined fit to the disappearence data of the Daya Bay experiment and the
appearance and disappearance data of the Tokai to Kamioka (T2K) one in the presence
of two models of new physics affecting neutrino oscillations, namely a model
where sterile neutrinos can propagate in a large compactified extra dimension
and a model where non-standard interactions (NSI) affect the neutrino
production and detection. We find that the Daya Bay T2K data
combination constrains the largest radius of the compactified extra dimensions
to be at 2 C.L. (for the inverted
ordering of the neutrino mass spectrum) and the relevant NSI parameters in the
range , for particular choices of
the charged parity violating phases.Comment: 18 pages, 10 figures, 4 tables; typos corrected; matches published
versio
Characterization of a disease-associated mutation affecting a putative splicing regulatory element in intron 6b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene
Cystic fibrosis (CF) is a common recessive disorder caused by >1600 mutations in the CF transmembrane conductance regulator (CFTR) gene. About 13% of CFTR mutations are classified as âsplicing mutations,â but for almost 40% of these, their role in affecting the pre-mRNA splicing of the gene is not yet defined. In this work, we describe a new splicing mutation detected in three unrelated Italian CF patients. By DNA analyses and mRNA studies, we identified the c.1002â1110_1113delTAAG mutation localized in intron 6b of the CFTR gene. At the mRNA level, this mutation creates an aberrant inclusion of a sequence of 101 nucleotides between exons 6b and 7. This sequence corresponds to a portion of intron 6b and resembles a cryptic exon because it is characterized by an upstream ag and a downstream gt sequence, which are most probably recognized as 5âČ- and 3âČ-splice sites by the spliceosome. Through functional analysis of this splicing defect, we show that this mutation abolishes the interaction of the splicing regulatory protein heterogeneous nuclear ribonucleoprotein A2/B1 with an intronic splicing regulatory element and creates a new recognition motif for the SRp75 splicing factor, causing activation of the cryptic exon. Our results show that the c.1002â1110_1113delTAAG mutation creates a new intronic splicing regulatory element in intron 6b of the CFTR gene exclusively recognized by SRp75
Small-scale distribution of metazoan meiofauna and sedimentary organic matter in subtidal sandy sediments (Mediterranean Sea)
While variations in sedimentary organic matter (OM) quantity, biochemical composition and nutritional quality as well as in meiofaunal abundance and assemblage composition at the macro- and mesoscale are relatively well known, information about variations at the microscale is much scarcer. To shed some light on this issue, we tested the null hypothesis by which abundance and composition of the meiofaunal assemblages, and the quantity, biochemical composition and nutritional quality of sedimentary organic matter in coastal shallow environments do not vary within a frame of 1 m2. No significant variation within the frame emerged for OM quantity, nutritional quality, biochemical composition and the abundance of meiofaunal assemblages. On the other hand, the composition of meiofaunal assemblages varied significantly within the frame and exhibited a clear segregation of assemblages farther to the shore, as a likely result of local micro-hydrodynamic conditions. Spatial autocorrelation analysis revealed that lipid and protein sedimentary contents had a random distribution, whereas carbohydrate and biopolymeric C contents and meiofaunal total abundance were characterized by a patchy distribution, with discrete peaks within the sub-frame squares (ca. 0.1 m2). Phytopigments showed a spatial positive autocorrelation distribution, following the micro-hydrodynamic pattern, with patches larger than the sub-frame square, but smaller than the entire one (1 m2). Overall, our results suggest that, within 1 m2 of subtidal sandy sediments, three replicates could be sufficient to assess correctly OM attributes and the abundance of meiofauna, but could be possibly inadequate for assessing meiofaunal assemblagesâ composition at a finer scale (<1 m2)
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