Universality or non-universality of absorption cross sections for extended objects

نویسندگان
چکیده

برای دانلود باید عضویت طلایی داشته باشید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Universality of infrared renormalons in hadronic cross sections

We discuss the role of infrared renormalons in power corrections to hadronic cross sections, including their universality. We show how perturbative renormalon structure arises near kinematic boundaries in the thrust distribution, the Drell-Yan cross section and radiative B decays. The leading infrared renormalon in each case is associated with jet evolution. Demanding that the combination of pe...

متن کامل

UNIVERSALITY AND TOLERANCE ( Extended

For any positive integers r and n, let H(r, n) denote the family of graphs on n vertices with maximum degree r, and let H(r, n, n) denote the family of bipartite graphs H on 2n vertices with n vertices in each vertex class, and with maximum degree r. On one hand, we note that any H(r, n)-universal graph must have Ω(n2−2/r) edges. On the other hand, for any n ≥ n0(r), we explicitly construct H(r...

متن کامل

A Boundary between Universality and Non-universality in Extended Spiking Neural P Systems

We solve the problem of finding the smallest possible universal spiking neural P system with extended rules. We give a universal spiking neural P system with extended rules and only 4 neurons. This is the smallest possible universal system of its kind. We prove this by showing that the set of problems solved by spiking neural P systems with 3 neurons is bounded above by NL, and so there exists ...

متن کامل

Extended squaraine dyes with large two-photon absorption cross-sections.

Extended bis(donor)-substituted squaraine chromophores exhibit very high two-photon cross-sections (as high as 33 000 GM) in the near-IR; these can be attributed to the combination of large transition dipoles with small detuning energies. The modulus of the third-order nonlinear optical susceptibility at 1.3 mum has been found to be 7.0 x 10-11 esu for one of these chromophores.

متن کامل

On the universality of cross sections of hadron -hadron(nuclei) collisions at superhigh energies

We analyze the pattern of the onset of complete absorption (the black limit) in the high energy hadron-hadron collisions. The black limit arises due to the hard and soft interaction dynamics as a function of the impact parameters b. Both hard and soft mechanisms provide universal dependence of the partial amplitude of the high energy elastic hadronhadron scattering on the impact parameter b and...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Physics Letters B

سال: 2000

ISSN: 0370-2693

DOI: 10.1016/s0370-2693(00)01077-7