27,270 research outputs found

### Master integrals for massless three-loop form factors

We summarize the results for the master integrals of the three-loop quark and
gluon form factor in massless QCD. Working in dimensional regularization we
extract poles up to 1/epsilon^6. The computational techniques involve, among
others, the expansion of higher transcendental functions and the Mellin-Barnes
method. The coefficients of the Laurent expansion in epsilon are given either
analytically or numerically to high precision.Comment: 8 pages, 1 figure; talk given at RADCOR 2009 - 9th International
Symposium on Radiative Corrections (Applications of Quantum Field Theory to
Phenomenology), October 25 - 30 2009, Ascona, Switzerlan

### Baryogenesis in the MSSM, nMSSM and NMSSM

We compare electroweak baryogenesis in the MSSM, nMSSM and NMSSM. We comment
on the different sources of CP violation, the phase transition and constraints
from EDM measurements.Comment: 6 pages, 4 figures. To appear in the proceedings of the 7th
Conference on Strong and Electroweak Matter (SEWM06), Brookhaven National
Laboratory, May 10-13, 200

### Reconstructing fully-resolved trees from triplet cover distances

It is a classical result that any finite tree with positively weighted edges, and without vertices of degree 2, is uniquely determined by the weighted path distance between each pair of leaves. Moreover, it is possible for a (small) strict subset L of leaf pairs to suffice for reconstructing the tree and its edge weights, given just the distances between the leaf pairs in L. It is known that any set L with this property for a tree in which all interior vertices have degree 3 must form a cover for T {that is, for each interior vertex v of T, L must contain a pair of leaves from each pair of the three components of T Ì¶ v. Here we provide a partial converse of this result by showing that if a set L of leaf pairs forms a cover of a certain type for such a tree T then T and its edge weights can be uniquely determined from the distances between the pairs of leaves in L. Moreover, there is a polynomial-time algorithm for achieving this reconstruction. The result establishes a special case of a recent question concerning `triplet covers', and is relevant to a problem arising in evolutionary genomics

### Distinguished minimal topological lassos

The ease with which genomic data can now be generated using Next Generation Sequencing technologies combined with a wealth of legacy data holds great promise for exciting new insights into the evolutionary relationships between and within the kingdoms of life. At the sub-species level (e.g. varieties or strains) certain edge weighted rooted trees with leaf set the set $X$ of organisms under consideration are often used to represent them. Called Dendrograms, it is well-known that they can be uniquely reconstructed from distances provided all distances on $X$ are known. More often than not, real biological datasets do not satisfy this assumption implying that the sought after dendrogram need not be uniquely determined anymore by the available distances with regards to topology, edge-weighting, or both. To better understand the structural properties a set \cL\subseteq {X\choose 2} has to satisfy to overcome this problem, various types of lassos have been introduced. Here, we focus on the question of when a lasso uniquely determines the topology of a dendrogram, that is, it is a topological lasso for it's underlying tree. We show that any set-inclusion minimal topological lasso for such a tree $T$ can be transformed into a structurally nice minimal topological lasso for $T$. Calling such a lasso a distinguished minimal topological lasso for $T$ we characterize them in terms of the novel concept of a cluster marker map for $T$. In addition, we present novel results concerning the heritability of such lassos in the context of the subtree and supertree problems

### Combined potential of future long-baseline and reactor experiments

We investigate the determination of neutrino oscillation parameters by
experiments within the next ten years. The potential of conventional beam
experiments (MINOS, ICARUS, OPERA), superbeam experiments (T2K, NOvA), and
reactor experiments (D-CHOOZ) to improve the precision on the ``atmospheric''
parameters $\Delta m^2_{31}$, $\theta_{23}$, as well as the sensitivity to
$\theta_{13}$ are discussed. Further, we comment on the possibility to
determine the leptonic CP-phase and the neutrino mass hierarchy if
$\theta_{13}$ turns out to be large.Comment: 4 pages, 4 figures, Talk given by T.S. at the NOW2004 workshop, Conca
Specchiulla (Otranto, Italy), 11--17 Sept. 200

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