19,927 research outputs found
Calculation of Reggeon Vertices in QCD
The method of calculation of effective vertices of interaction of the
Reggeized gluon and quark with particles in QCD in the next-to-leading order is
developed. The method is demonstrated in the case of already known vertices of
both gluon-gluon and quark-quark transitions in the scattering of gluons and
quarks on the Reggeized gluon. It is used for the calculation of the
gluon-quark transition in the scattering on the Reggeized quark.Comment: 27 pages, LaTex, 1 figure, uses axodraw.st
The Quark Impact Factors
We calculate in the next-to-leading approximation the non-forward quark
impact factors for both singlet and octet color representation in the
-channel. The integral representation of the octet impact factor in the
general case of arbitrary space-time dimension and massive quark flavors is
used to check the so-called "second bootstrap condition" for the gluon
Reggeization at the next-to-leading logarithmic approximation in perturbative
QCD. We find that it is satisfied for both helicity conserving and
non-conserving parts. The integrations are then performed for the explicit
calculation of the impact factors in the massless quark case.Comment: 23 pages, LaTeX, 1 EPS figure, uses epsf.sty and axodraw.st
Electroproduction of two light vector mesons in next-to-leading BFKL: study of systematic effects
The forward electroproduction of two light vector mesons is the first example
of a collision process between strongly interacting colorless particles for
which the amplitude can be written completely within perturbative QCD in the
Regge limit with next-to-leading accuracy. In a previous paper we have given a
numerical determination of the amplitude in the case of equal photon
virtualities by using a definite representation for the amplitude and a
definite optimization method for the perturbative series. Here we estimate the
systematic uncertainty of our previous determination, by considering a
different representation of the amplitude and different optimization methods of
the perturbative series. Moreover, we compare our result for the differential
cross section at the minimum momentum transfer with a different approach, based
on collinear kernel improvement.Comment: 17 pages, 11 figures; journal version, new figures and discussion
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The quark part of the non-forward BFKL kernel and the ``bootstrap'' for the gluon Reggeization
We calculate the quark part of the kernel of the generalized non-forward BFKL
equation at non-zero momentum transfer in the next-to-leading logarithmic
approximation. Along with the quark contribution to the gluon Regge trajectory,
this part includes pieces coming from the quark-antiquark production and from
the quark contribution to the radiative corrections in one-gluon production in
the Reggeon-Reggeon collisions. The results obtained can be used for an
arbitrary representation of the colour group in the channel. Using the
results for the adjoint representation, we demonstrate explicitly the
fulfillment of the ``bootstrap'' condition for the gluon Reggeization in the
next-to-leading logarithmic approximation in the part concerning the quark
contribution.Comment: 26 pages, LaTeX, uses axodraw.sty; revised final comment; to appear
on Phys. Rev.
The Gluon Impact Factors
We calculate in the next-to-leading approximation the non-forward gluon
impact factors for arbitrary color state in the -channel. In the case of the
octet state we check the so-called "second bootstrap condition" for the gluon
Reggeization in QCD, using the integral representation for the impact factors.
The condition is fulfilled in the general case of an arbitrary space-time
dimension and massive quark flavors for both helicity conserving and
non-conserving parts.Comment: 32 pages, LaTeX, 1 EPS figure, uses epsf.sty and axodraw.st
Narrative, postmodernity and the problem of "religious illiteracy"
It is popular nowadays to claim not only that narrative is the most effective way to communicate religious knowledge but also that narrative provides the framework within which religious lifestyles and practices are meaningful. However, many today lack familiarity with the narratives of traditional religions. In other words, they suffer from âreligious illiteracyâ. This article considers the problem of how religion can become meaningful to such people. The view that religion can be divested of its outdated cultural accoutrements and presented in a form that resonates with postmodern secular culture is considered and found to be problematic. If acquiring a religion is like acquiring a culture, or a language, it seems unlikely that a deeper appreciation of a religious tradition will be facilitated by divesting it of its traditional cultural expressions. Moreover, the view that religious lifestyles should be emphasised rather than religious belief seems to be more a symptom of the problem of âreligious illiteracyâ than a solution to it. The article concludes that both of these responses fail to provide a solution to the problem and that an alternative strategy is urgently required
Metaphor, religious language and religious experience
Is it possible to talk about God without either misrepresentation or failing to assert anything of significance? The article begins by reviewing how, in attempting to answer this question, traditional theories of religious language have failed to sidestep both potential pitfalls adequately. After arguing that recently developed theories of metaphor seem better able to shed light on the nature of religious language, it considers the claim that huge areas of our language and, consequently, of our experience are shaped by metaphors. Finally, it considers some of the more significant implications of this claim for our understanding of both religious language and religious experience
The pragmatics of defining religion in a multi-cultural world
Few seem to have difficulty in distinguishing between religious and secular institutions, yet there is widespread disagreement regarding what "religion" actually means. Indeed, some go so far as to question whether there is anything at all distinctive about religions. Hence, formulating a definition of "religion" that can command wide assent has proven to be an extremely difficult task. In this article I consider the most prominent of the many rival definitions that have been proposed, the majority falling within three basic types: intellectual, affective and functional definitions. I conclude that there are pragmatic reasons for favouring the formerly popular view that essentialist definitions of "religions" are inadequate, and that religions should be construed, instead, as possessing a number of "family resemblances". In so arguing, I provide a response to the view that there is nothing distinctive about religions, as well as to the recent claim that religions do not exist
Internal realism, religious pluralism and ontology
Internalist pluralism is an attractive and elegant theory. However, there are two apparently powerful objections to this approach that prevent its widespread adoption. According to the first objection, the resulting analysis of religious belief systems is intrinsically atheistic; while according to the second objection, the analysis is unsatisfactory because it allows religious objects simply to be defined into existence. In this article, I demonstrate that an adherent of internalist pluralism can deflect both of these objections, and in the course of so arguing, I deploy a distinction between âconceptual-scheme targetabilityâ and âsuccessful conceptual-scheme targetingâ
A solution of a problem of Sophus Lie: Normal forms of 2-dim metrics admitting two projective vector fields
We give a complete list of normal forms for the 2-dimensional metrics that
admit a transitive Lie pseudogroup of geodesic-preserving transformations and
we show that these normal forms are mutually non-isometric. This solves a
problem posed by Sophus Lie.Comment: This is an extended version of the paper that will appear in Math.
Annalen. Some typos were corrected, references were updated, title was
changed (as in the journal version). 31 page
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