40,219 research outputs found
Present and Future in Semileptonic B Decays
In this talk I review the status of our ability to extract the CKM matrix
elements |Vub| and |Vcb| from semileptonic decays. I will review both exclusive
and inclusive methods and put a strong emphasis on how to ensure keeping the
extractions model independent.Comment: 10 pages, Invited plenary talk presented at 9th International
Symposium on Heavy Flavor Physics, Caltech, Sep. 10-13, 200
Home Education: Globalization Otherwise?
Home Education seems to be a successful way to educate. Academic results and socialization processes in home education are promising. Already home education is global, home educators everywhere educate their children themselves without schools. They develop new forms of local and international co-operation. Is home education an impulse to a renewing of modern education? Is home education globalization otherwise?home education, globalization, educational politics, pedagogy
Periodicity of free subgroup numbers modulo prime powers
We completely characterise when the sequence of free subgroup numbers of a
finitely generated virtually free group is ultimately periodic modulo a given
prime power.Comment: AmS-LaTeX; 18 page
Heavy Quark Fragmenting Jet Functions
Heavy quark fragmenting jet functions describe the fragmentation of a parton
into a jet containing a heavy quark, carrying a fraction of the jet momentum.
They are two-scale objects, sensitive to the heavy quark mass, , and to a
jet resolution variable, . We discuss how cross sections for heavy
flavor production at high transverse momentum can be expressed in terms of
heavy quark fragmenting jet functions, and how the properties of these
functions can be used to achieve a simultaneous resummation of logarithms of
the jet resolution variable, and logarithms of the quark mass. We calculate the
heavy quark fragmenting jet function at , and the gluon and light quark fragmenting jet functions into a
heavy quark, and , at . We verify that, in the limit in which the jet invariant mass is
much larger than , the logarithmic dependence of the fragmenting jet
functions on the quark mass is reproduced by the heavy quark fragmentation
functions. The fragmenting jet functions can thus be written as convolutions of
the fragmentation functions with the matching coefficients ,
which depend only on dynamics at the jet scale. We reproduce the known matching
coefficients at , and we obtain the
expressions of the coefficients and at
. Our calculation provides all the perturbative
ingredients for the simultaneous resummation of logarithms of and
.Comment: 48 pages, 11 figure
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