Possible evidence for the disk origin for the powering of jets in Sgr A* and nearby elliptical galaxies

The predicted radio flux for nearby ellipticals by the canonical ADAF(advection-dominated accretion flow) model is well above the observations. If the mass accretion rate favored by the numerical simulation were adopted, the ADAF model would also significantly overpredict the radio flux of Sgr A*. On the observational side, strong evidence for the existence of jets in Sgr A$^*$ and these ellipticals has been obtained. Based on these facts, we propose a truncated ADAF model for these sources. We assume that the accretion disk is truncated at a certain radius within which a jet forms by extracting the energy of the disk therefore the radio flux is greatly suppressed due to the radiative truncation of the disk and the fits to the observational data are excellent. For example, for Sgr A*, the model fits the spectrum very well from radio including the ``excess'' below the break frequency to hard X-ray under a high accretion rate near the simulation value; for M87, the predicted upper limit of the jet location is 24 $R_g$, in excellent agreement with the observational result of < 30 $R_g$. The success of the model supplies a possible piece of evidence for the disk rather than the hole origin for the powering of jets.Comment: 8 pages, 5 figures, uses mn.sty, accepted by MNRA

Azimuthal Asymmetric Distribution of Hadrons Inside a Jet at Hadron Collider

We study the azimuthal asymmetric distribution of hadrons inside a high energy jet in the single transverse polarized proton proton scattering, coming from the Collins effect multiplied by the quark transversity distribution. We argue that the Collins function in this process is the same as that in the semi-inclusive deep inelastic scattering. The experimental study of this process will provide us important information on the quark transversity distribution and test the universality of the fragmentation functions.Comment: 10 pages, 4 figure

Luminous hot accretion disks

We find a new two-temperature hot branch of equilibrium solutions for stationary accretion disks around black holes. In units of Eddington accretion rate defined as $10L_{\rm Edd}/c^2$, the accretion rates to which these solutions correspond are within the range \dot{m}_1 \la \dot{m} \la 1, here $\dot{m}_1$ is the critical rate of advecti$. In these solutions, the energy loss rate of the ions by Coulomb energy transfer between the ions and electrons is larger than the viscously heating rate and it is the advective heating together with the viscous dissipation that balances the Coulomb cooling of ions. When$\dot{m}_1 \la \dot{m} \la \dot{m}_2$, where$\dot{m}_2 \sim 5 \dot{m}_1 < 1$, the accretion flow remains hot throughout the disk. When$\dot{m}_2 \la \dot{m}\la 1$, Coulomb interaction will cool the inner region of the disk within a certain radius ($r_{\rm tr} \sim$ several -- tens of Schwarzschild radii or larger depending on the accretion rate and the outer boundary condition) and the disk will collapse onto the equatorial plane and form an optically thick cold annulus. Compared to ADAF, these hot solutions are much more luminous because of the high accretion rate and efficiency, therefore, we name them luminous hot accretion disks.Comment: 12 pages, 6 figures, uses mn.sty, the final version accepted by MNRAS, discussion extended to emphasize the difference between ADAF and my mode

Transverse Momentum Resummation for Dijet Correlation in Hadronic Collisions

We study the transverse momentum resummation for dijet correlation in hadron collisions based on the Collins-Soper-Sterman formalism. The complete one-loop calculations are carried out in the collinear factorization framework for the differential cross sections at low imbalance transverse momentum between the two jets. Important cross checks are performed to demonstrate that the soft divergences cancelled out between different diagrams, and in particular, those associated with final state jets. The leading and sub-leading logarithms are identified. All order resummation is derived following the transverse momentum dependent factorization at this order. Its phenomenological applications are also presented.Comment: 51 pages, 10 figure

Long Range Correlation in Higgs Boson Plus Two Jets Production at the LHC

We study Higgs boson plus two high energy jets production at the LHC in the kinematics where the two jets are well separated in rapidity. The partonic processes are dominated by the t-channel weak boson fusion (WBF) and gluon fusion (GF) contributions. We derive the associated QCD resummation formalism for the correlation analysis where the total transverse momentum q_\perp of the Higgs boson and two jets is small. Because of different color structures, the resummation results lead to distinguished behaviors: the WBF contribution peaks at relative low q_\perp while all GF channel contributions are strongly de-correlated and spread to a much wider q_\perp range. By applying a kinematic cut on q_\perp, one can effectively increase the WBF signal to the GF background by a significant factor. This greatly strengthens the ability to investigate the WBF channel in Higgs boson production and study the couplings of Higgs to electroweak bosons.Comment: 9 pages, 2 figure