10,534 research outputs found
Corrections to Quark Asymmetries at LEP
The most precise measurement of the weak mixing angle sin^2(theta) at LEP is
from the forward-backward asymmetry e+e- --> bbbar at the Z-pole. In this note
the QED and electroweak radiative corrections to obtain the pole asymmetry from
the measured asymmetry for b- and c-quarks have been calculated using ZFITTER,
which has been amended to allow a consistent treatment of partial two-loop
corrections for the b-quark final asymmetries.
A total correction of dAfbb=0.0019+/-0.0002 and dAfbc=0.0064+/-0.0001 has
been found, where the remaining theoretical uncertainty is much too small to
explain the apparent discrepancy between sin^2(theta) obtained from Afbb and
from the left-right asymmetry at SLD
Forfeiture of Attorney\u27s Fees Under RICO and CCE
We present the matching relations of the variable flavor number scheme at next-to-leading order, which are of importance to define heavy quark partonic distributions for the use at high energy colliders such as Tevatron and the LHC. The consideration of the two-mass effects due to both charm and bottom quarks, having rather similar masses, are important. These effects have not been considered in previous investigations. Numerical results are presented for a wide range of scales. We also present the corresponding contributions to the structure function
The Role of Differentially Expressed miRNAs and Potential miRNA-mRNA Regulatory Network in Prostate Cancer Progression and Metastasis
Purpose: Aberrant expression of microRNAs (miRNAs) has been discovered in prostate cancer progression however their function is not well understood, thereby further investigation is required to understand the importance of underlying mechanisms and their involvement in multiple signaling pathways, as well as their potential as therapeutic targets. In this study the role and expression levels of three miRNAs were evaluated: miR-21, miR-221 and miR-200c in different prostate cancer cell lines. In addition, based on the latest studies on miRNAs function, their association with other target genes and molecules were analyzed using bioinformatic tools.
Methods: Three PCa cell lines PC3, LNCaP and VCaP and normal prostate epithelial cell line PNT1A were screened for miRNA expression levels using qPCR. miRNA target genes and their association with signaling pathways were analyzed through several Network and pathway analysis online tools.
Findings: Upregulation of miR-21 and miR-221 was observed in PC3 and VCaP prostate cancer cells, respectively. According to KEGG analysis, we found that Hippo signaling pathway and cytokine-cytokine receptor interactions were affected by miR-21 while miR-221 would interfere with ECM-receptor interaction, Fatty acid elongation and Huntington disease molecular networks. Exposure of PC3 cells to TGF-β (10 µM) caused upregulation of miR-21 with the evidence with increased invasion potential.
Discussion and Conclusion: miRNAs could regulate several genes in multiple signaling pathways. Here, we demonstrated that in a panel of PCa cell lines, both mir-21 and miR-221 expressions were upregulated. miR-21 may be a dignostic and prognosticbiomarker for PCa
The Three Loop Two-Mass Contribution to the Gluon Vacuum Polarization
We calculate the two-mass contribution to the 3-loop vacuum polarization of
the gluon in Quantum Chromodynamics at virtuality for general masses
and also present the analogous result for the photon in Quantum
Electrodynamics.Comment: 5 pages Late
Subleading Logarithmic QED Initial State Corrections to to
Using the method of massive operator matrix elements, we calculate the
subleading QED initial state radiative corrections to the process for the first three logarithmic contributions from
to and compare their effects to the leading
contribution and one more subleading term .
The calculation is performed in the limit of large center of mass energies
squared . These terms supplement the known corrections to
, which were completed recently. Given the high precision at
future colliders operating at very large luminosity, these corrections are
important for concise theoretical predictions. The present calculation needs
the calculation of one more two--loop massive operator matrix element in QED.
The radiators are obtained as solutions of the associated Callen--Symanzik
equations in the massive case. The radiators can be expressed in terms of
harmonic polylogarithms to weight {\sf w = 6} of argument and and
in Mellin space by generalized harmonic sums. Numerical results are
presented on the position of the peak and corrections to the width,
. The corrections calculated result into a final theoretical accuracy
for and which is estimated to be of O(30 keV) at
an anticipated systematic accuracy at the FCC\_ee of \sim 100 keV. This
precision cannot be reached, however, by including only the corrections up to
.Comment: 58 pages, 3 Figure
The unpolarized two-loop massive pure singlet Wilson coefficients for deep-inelastic scattering
We calculate the massive two--loop pure singlet Wilson coefficients for heavy
quark production in the unpolarized case analytically in the whole kinematic
region and derive the threshold and asymptotic expansions. We also recalculate
the corresponding massless two--loop Wilson coefficients. The complete
expressions contain iterated integrals with elliptic letters. The contributing
alphabets enlarge the Kummer-Poincar\'e letters by a series of square-root
valued letters. A new class of iterated integrals, the Kummer-elliptic
integrals, are introduced. For the structure functions and we also
derive improved asymptotic representations adding power corrections. Numerical
results are presented.Comment: 42, pages Latex, 8 Figure
The Initial State QED Corrections to Annihilation to a Neutral Vector Boson Revisited
We calculate the non-singlet, the pure singlet contribution, and their
interference term, at due to electron-pair initial state
radiation to annihilation into a neutral vector boson in a direct
analytic computation without any approximation. The correction is represented
in terms of iterated incomplete elliptic integrals. Performing the limit we find discrepancies with the earlier results of
Ref.~\cite{Berends:1987ab} and confirm results obtained in
Ref.~\cite{Blumlein:2011mi} where the effective method of massive operator
matrix elements has been used, which works for all but the power corrections in
. In this way, we also confirm the validity of the factorization of
massive partons in the Drell-Yan process. We also add non-logarithmic terms at
which have not been considered in \cite{Berends:1987ab}. The
corrections are of central importance for precision analyzes in
annihilation into at high luminosity.Comment: 4 pages Latex, 2 Figures, several style file
The two-mass contribution to the three-loop pure singlet operator matrix element
We present the two-mass QCD contributions to the pure singlet operator matrix
element at three loop order in x-space. These terms are relevant for
calculating the structure function at as well as
for the matching relations in the variable flavor number scheme and the heavy
quark distribution functions at the same order. The result for the operator
matrix element is given in terms of generalized iterated integrals that include
square root letters in the alphabet, depending also on the mass ratio through
the main argument. Numerical results are presented.Comment: 28 papges Latex, 3 figure
The Two-mass Contribution to the Three-Loop Gluonic Operator Matrix Element
We calculate the two-mass QCD contributions to the massive operator matrix
element at in analytic form in Mellin
- and -space, maintaining the complete dependence on the heavy quark mass
ratio. These terms are important ingredients for the matching relations of the
variable flavor number scheme in the presence of two heavy quark flavors, such
as charm and bottom. In Mellin -space the result is given in the form of
nested harmonic, generalized harmonic, cyclotomic and binomial sums, with
arguments depending on the mass ratio. The Mellin inversion of these quantities
to -space gives rise to generalized iterated integrals with square root
valued letters in the alphabet, depending on the mass ratio as well. Numerical
results are presented.Comment: 99 pages LATEX, 2 Figure
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