2,732 research outputs found
Probing the lightest new gauge boson in the littlest Higgs model via the processes at the ILC
The neutral gauge boson with the mass of hundreds GeV, is the lightest
particle predicted by the littlest Higgs(LH) model, and such particle should be
the first signal of the LH model at the planed ILC if it exists indeed. In this
paper, we study some processes of the production associated with the
fermion pair at the ILC, i.e., . The studies
show that the most promising processes to detect among are , and they can
produce the sufficient signals in most parameter space preferred by the
electroweak precision data at the ILC. On the other hand, the signal produced
via the certain decay modes is typical and such signal can be easily
identified from the SM background. Therefore, , the lightest gauge boson
in the LH model would be detectable at the photon collider realized at the ILC.Comment: 12 pages, 4 figure
The production of the new gauge boson via collision in the littlest Higgs model
The new lightest gauge boson with mass of a few hundred GeV is
predicted in the littlest Higgs model. should be accessible in the planed
ILC and the observation of such particle can strongly support the littlest
Higgs model. The realization of and collision will
open a wider window to probe . In this paper, we study the new gauge boson
production processes and
at the ILC. Our results show that the production
cross section of the process is less than one fb
in the most parameter spaces while the production cross section of the process
can reach the level of tens fb and even
hundreds of fb in the sizable parameter spaces allowed by the electroweak
precision data. With the high luminosity, the sufficient typical signals could
be produced, specially via . Because the
final electron and photon beams can be easily identified and the signal can be
easily distinguished from the background produced by and decaying,
should be detectable via collision at the ILC. Therefore, the
processes and
provide a useful way to detect and test the littlest Higgs model.Comment: 15 pages, 3 figures. Some typos have been corrected, we have added
some new references, and there are also some changes in equation 1
Highly-Sensitive Thin Film THz Detector Based on Edge Metal-Semiconductor-Metal Junction
Terahertz (THz) detectors have been extensively studied for various applications such as security, wireless communication, and medical imaging. In case of metal-insulator-metal (MIM) tunnel junction THz detector, a small junction area is desirable because the detector response time can be shortened by reducing it. An edge metal-semiconductor-metal (EMSM) junction has been developed with a small junction area controlled precisely by the thicknesses of metal and semiconductor films. The voltage response of the EMSM THz detector shows the clear dependence on the polarization angle of incident THz wave and the responsivity is found to be very high (similar to 2,169 V/W) at 0.4 THz without any antenna and signal amplifier. The EMSM junction structure can be a new and efficient way of fabricating the nonlinear device THz detector with high cut-off frequency relying on extremely small junction area
A Genome-Wide Association Study Identifies Novel Alleles Associated with Hair Color and Skin Pigmentation
We conducted a multi-stage genome-wide association study of natural hair color in more than 10,000 men and women of European ancestry from the United States and Australia. An initial analysis of 528,173 single nucleotide polymorphisms (SNPs) genotyped on 2,287 women identified IRF4 and SLC24A4 as loci highly associated with hair color, along with three other regions encompassing known pigmentation genes. We confirmed these associations in 7,028 individuals from three additional studies. Across these four studies, SLC24A4 rs12896399 and IRF4 rs12203592 showed strong associations with hair color, with p = 6.0×10−62 and p = 7.46×10−127, respectively. The IRF4 SNP was also associated with skin color (p = 6.2×10−14), eye color (p = 6.1×10−13), and skin tanning response to sunlight (p = 3.9×10−89). A multivariable analysis pooling data from the initial GWAS and an additional 1,440 individuals suggested that the association between rs12203592 and hair color was independent of rs1540771, a SNP between the IRF4 and EXOC2 genes previously found to be associated with hair color. After adjustment for rs12203592, the association between rs1540771 and hair color was not significant (p = 0.52). One variant in the MATP gene was associated with hair color. A variant in the HERC2 gene upstream of the OCA2 gene showed the strongest and independent association with hair color compared with other SNPs in this region, including three previously reported SNPs. The signals detected in a region around the MC1R gene were explained by MC1R red hair color alleles. Our results suggest that the IRF4 and SLC24A4 loci are associated with human hair color and skin pigmentation
The Reproducibility of Lists of Differentially Expressed Genes in Microarray Studies
Reproducibility is a fundamental requirement in scientific experiments and clinical contexts. Recent publications raise concerns about the reliability of microarray technology because of the apparent lack of agreement between lists of differentially expressed genes (DEGs). In this study we demonstrate that (1) such discordance may stem from ranking and selecting DEGs solely by statistical significance (P) derived from widely used simple t-tests; (2) when fold change (FC) is used as the ranking criterion, the lists become much more reproducible, especially when fewer genes are selected; and (3) the instability of short DEG lists based on P cutoffs is an expected mathematical consequence of the high variability of the t-values. We recommend the use of FC ranking plus a non-stringent P cutoff as a baseline practice in order to generate more reproducible DEG lists. The FC criterion enhances reproducibility while the P criterion balances sensitivity and specificity
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
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