378 research outputs found
The Subaru/XMM-Newton Deep Survey (SXDS) -VII. Clustering Segregation with Ultraviolet and Optical Luminosities of Lyman-Break Galaxies at z~3
We investigate clustering properties of Lyman-break galaxies (LBGs) at z~3
based on deep multi-waveband imaging data from optical to near-infrared
wavelengths in the Subaru/XMM-Newton Deep Field. The LBGs are selected by U-V
and V-z' colors in one contiguous area of 561 arcmin^2 down to z'=25.5. We
study the dependence of the clustering strength on rest-frame UV and optical
magnitudes, which can be indicators of star formation rate and stellar mass,
respectively. The correlation length is found to be a strong function of both
UV and optical magnitudes with brighter galaxies being more clustered than
faint ones in both cases. Furthermore, the correlation length is dependent on a
combination of UV and optical magnitudes in the sense that galaxies bright in
optical magnitude have large correlation lengths irrespective of UV magnitude,
while galaxies faint in optical magnitude have correlation lengths decreasing
with decreasing UV brightness. These results suggest that galaxies with large
stellar masses always belong to massive halos in which they can have various
star formation rates, while galaxies with small stellar masses reside in less
massive halos only if they have low star formation rates. There appears to be
an upper limit to the stellar mass and the star formation rate which is
determined by the mass of hosting dark halos.Comment: 16 pages, 15 figures, accepted for publication in Ap
Haplotype defined by the MLH1-93G/A polymorphism is associated with MLH1 promoter hypermethylation in sporadic colorectal cancers
Luminosity dependent clustering of star-forming BzK galaxies at redshift 2
We use the BzK color selection proposed by Daddi et al. (2004) to obtain a
sample of 1092 faint star-forming galaxies (hereafter sBzKs) from 180 arcmin^2
in the Subaru Deep Field. This sample represents star-forming galaxies at 1.4 <
z < 2.5 down to K(AB)=23.2, which roughly corresponds to a stellar-mass limit
of ~ 1 x 10^{10} Msun. We measure the angular correlation function (ACF) of
these sBzKs to be w(theta) = (0.58 +- 0.13) x theta["]^{-0.8} and translate the
amplitude into the correlation length assuming a reasonable redshift
distribution. The resulting value, r0 = 3.2^{+0.6}_{-0.7} h^{-1} Mpc, suggests
that our sBzKs reside in haloes with a typical mass of 2.8 x 10^{11} Msun.
Combining this halo mass estimate with those for brighter samples of Kong et
al. (2006), we find that the mass of dark haloes largely increases with K
brightness, a measure of the stellar mass. Comparison with other galaxy
populations suggests that faint sBzKs (K(AB)<23.2) and Lyman Break Galaxies at
z ~ 2 are similar populations hosted by relatively low-mass haloes, while
bright sBzKs (K(AB)<21) reside in haloes comparable to or more massive than
those of Distant Red Galaxies and Extremely Red Objects. Using the extended
Press-Schechter formalism, we predict that present-day descendants of haloes
hosting sBzKs span a wide mass range depending on K brightness, from lower than
that of the Milky Way up to those of richest clusters.Comment: 14 pages, 9 figures, accepted for publication in Ap
Improved Term of the Electron Anomalous Magnetic Moment
We report a new value of electron , or , from 891 Feynman diagrams
of order . The FORTRAN codes of 373 diagrams containing closed
electron loops have been verified by at least two independent formulations. For
the remaining 518 diagrams, which have no closed lepton loop, verification by a
second formulation is not yet attempted because of the enormous amount of
additional work required. However, these integrals have structures that allow
extensive cross-checking as well as detailed comparison with lower-order
diagrams through the renormalization procedure. No algebraic error has been
uncovered for them. The numerical evaluation of the entire term by
the integration routine VEGAS gives , where the
uncertainty is obtained by careful examination of error estimates by VEGAS.
This leads to ,
where the uncertainties come from the term, the estimated
uncertainty of term, and the inverse fine structure constant,
, measured by atom interferometry combined
with a frequency comb technique, respectively. The inverse fine structure
constant derived from the theory and the Seattle
measurement of is .Comment: 64 pages and 10 figures. Eq.(16) is corrected. Comments are added
after Eq.(40
Improved Term of the Muon Anomalous Magnetic Moment
We have completed the evaluation of all mass-dependent QED
contributions to the muon , or , in two or more different
formulations. Their numerical values have been greatly improved by an extensive
computer calculation. The new value of the dominant term is 132.6823 (72), which supersedes the old value 127.50 (41).
The new value of the three-mass term
is 0.0376 (1). The term is crudely estimated to
be about 0.005 and may be ignored for now. The total QED contribution to
is , where 0.02 and
1.15 are uncertainties in the and terms and 0.85 is from
the uncertainty in measured by atom interferometry. This raises the
Standard Model prediction by , or about 1/5 of the
measurement uncertainty of . It is within the noise of current
uncertainty () in the estimated hadronic
contributions to .Comment: Appendix A has been rewritten extensively. It includes the 4th-order
calculation for illustration. Version accepted by PR
Tenth-Order Lepton Anomalous Magnetic Moment -- Sixth-Order Vertices Containing Vacuum-Polarization Subdiagrams
This paper reports the values of contributions to the electron g-2 from 300
Feynman diagrams of the gauge-invariant Set III(a) and 450 Feynman diagrams of
the gauge-invariant Set III(b). The evaluation is carried out in two versions.
Version A is to start from the sixth-order magnetic anomaly M_6 obtained in the
previous work. The mass-independent contributions of Set III(a) and Set III(b)
are 2.1275 (2) and 3.3271 (6) in units of (alpha/pi)^5, respectively. Version B
is based on the recently-developed automatic code generation scheme. This
method yields 2.1271 (3) and 3.3271 (8) in units of (alpha/pi)^5, respectively.
They are in excellent agreement with the results of the first method within the
uncertainties of numerical integration. Combining these results as
statistically independent we obtain the best values, 2.1273 (2), and 3.3271 (5)
times (alpha/pi)^5, for the mass-independent contributions of the Set III(a)
and Set III(b), respectively. We have also evaluated mass-dependent
contributions of diagrams containing muon and/or tau-particle loop. Including
them the total contribution of Set III(a) is 2.1349 (2) and that of Set III(b)
is 3.3299 (5) in units of (alpha/pi)^5. The total contributions to the muon g-2
of various leptonic vacuum-polarization loops of Set III(a) and Set III(b) are
112.418 (32) and 15.407 (5) in units of (alpha/pi)^5, respectively.Comment: 31 pages, 4 figure
Monitoring Minute chances of Magnetic Maekers\u27 Susveptability by SV-GMR Needle-Type Probe
The aim of this study is to present the novel methodology for magnetic markers immunoassay measurements by spin valve giant magnetoresistive (SV-GMR) needle probe. Extremely small size and specific construction of this probe type allow detecting the changes of complex susceptibility directly from the sample. The needle-type probe consists of four SV-GMR elements connected in a Wheatstone bridge and it has sensitivity of 11 V/ T. The SV-GMR sensing element has dimensions of 40 m 75 m. This paper presents a setup feasible to perform spectroscopic magnetic markers measurement. It includes data related to signal changes caused by the magnetic markers dilution. It shows the influence of particle size changes (120 nm, 1 m, 3.5 m, 6.5 m) on real and imaginary parts of the complex susceptibility of the specimen. While performing measurements, probe sensing elements were placed inside the sample. Monitoring changes of samples susceptibility allows performing homogenous immunoassay measurements in a liquid phase by SV-GMR probe. Based on the measurement results, analytical model of changes of complex susceptibility is derived and described
Inclusive dileptonic rare B decays with an extra generation of vector-like quarks
We investigate the leading effects of extending the Standard Model of
electroweak interactions by an extra iso-singlet up- and down- type quark pair
on various distributions and total branching ratio of the inclusive B-> X_s l^+
l^- (l =e,\mu) rare B decays. The presence of the extra vector-like down quark
results in the non-unitarity of the extended quark mixing matrix V, which
in turn leads to b-> s FCNC at the tree level proportional to (V^\dagger
V)_{sb}. On the other hand, the effective penguin and box vertex functions are
sensitive to the mass of the extra iso-singlet up quark m_U. The experimental
upper bound on BR(B-> X_s \mu^+ \mu^-) is used to constrain the parameters of
the model. It is shown that the shapes of the differential branching ratio and
forward-backward asymmetry distribution are very sensitive to the value of the
model parameters. We also calculate the CP aymmetry distribution of the
dileptonic decay in the vector-like quark model. It is shown that, for a
typical choice of the model parameters, asymmetries up to around 10% can be
achieved for certain values of the dilepton invariant mass.Comment: 15 pages, 2 figure
New-physics contributions to the forward-backward asymmetry in B -> K* mu+ mu-
We study the forward-backward asymmetry (AFB) and the differential branching
ratio (DBR) in B -> K* mu+ mu- in the presence of new physics (NP) with
different Lorentz structures. We consider NP contributions from vector-axial
vector (VA), scalar-pseudoscalar (SP), and tensor (T) operators, as well as
their combinations. We calculate the effects of these new Lorentz structures in
the low-q^2 and high-q^2 regions, and explain their features through analytic
approximations. We find two mechanisms that can give a significant deviation
from the standard-model predictions, in the direction indicated by the recent
measurement of AFB by the Belle experiment. They involve the addition of the
following NP operators: (i) VA, or (ii) a combination of SP and T (slightly
better than T alone). These two mechanisms can be distinguished through
measurements of DBR in B -> K* mu+ mu- and AFB in B -> K mu+ mu-.Comment: 33 pages, revtex, 9 figures. Paper originally submitted with the
wrong figures. This is corrected in the replacement. An incorrect factor of 2
found in a formula. This is corrected and figures modified. Conclusions
unchanged. Typos correcte
factorization of exclusive processes
We prove factorization theorem in perturbative QCD (PQCD) for exclusive
processes by considering and . The relevant form factors are expressed as the convolution of hard
amplitudes with two-parton meson wave functions in the impact parameter
space, being conjugate to the parton transverse momenta . The point is
that on-shell valence partons carry longitudinal momenta initially, and acquire
through collinear gluon exchanges. The -dependent two-parton wave
functions with an appropriate path for the Wilson links are gauge-invariant.
The hard amplitudes, defined as the difference between the parton-level
diagrams of on-shell external particles and their collinear approximation, are
also gauge-invariant. We compare the predictions for two-body nonleptonic
meson decays derived from factorization (the PQCD approach) and from
collinear factorization (the QCD factorization approach).Comment: 11 pages, REVTEX, 5 figure
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