Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userProbing double hadron resonances by the complex scaling method
58
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Many newly discovered excited states are interpreted as bound states of hadrons. Can these hadrons also form resonant states? In this paper, we extend the complex scaling method (CSM) to calculate the bound state and resonant state consistently for the $Lambda_c D(bar D)$ and $Lambda_c Lambda_c (bar Lambda_c)$ systems. For these systems, the $pi, eta, rho$ meson exchange contributions are suppressed, the contributions of intermediate- and short-range forces from $sigma/omega$ exchange are dominant. Our results indicate that $Lambda_c D$ system can not form bound state and resonant state. There exist resonant states in a wide range of parameters for $Lambda_c bar D$ and $Lambda_c Lambda_c (bar Lambda_c)$ systems. For these systems, the larger bound state energy, the easier to form resonant states. Among all the resonant states, the energies and widths of the P wave resonant states are smaller and more stable, which is possible to be observed in the experiments. The energies of D and F wave resonant states can reach dozens of MeV and the widths can reach hundreds of MeV.
rate research
Read More
We study the resonance spectroscopy of the proton-rich nucleus 7B in the 4He+p+p+p cluster model. Many-body resonances are treated on the correct boundary condition as the Gamow states using the complex scaling method. We predict five resonances of 7B and evaluate the spectroscopic factors of the 6Be-p components. The importance of the 6Be(2+)-p component is shown in several states of 7B, which is a common feature of 7He, a mirror nucleus of 7B. For only the ground state of 7B, the mixing of 6Be(2+) state is larger than that of 6He(2+) in 7He, which indicates the breaking of the mirror symmetry. This is caused by the small energy difference between 7B and the excited 6Be(2+) state, whose origin is the Coulomb repulsion.
It is shown that the continuum level density (CLD) at unbound energies can be calculated with the complex scaling method (CSM), in which the energy spectra of bound states, resonances and continuum states are obtained in terms of $L^2$ basis functions. In this method, the extended completeness relation is applied to the calculation of the Green functions, and the continuum-state part is approximately expressed in terms of discretized complex scaled continuum solutions. The obtained result is compared with the CLD calculated exactly from the scattering phase shift. The discretization in the CSM is shown to give a very good description of continuum states. We discuss how the scattering phase shifts can inversely be calculated from the discretized CLD using a basis function technique in the CSM.
The complex scaling method (CSM) is a useful similarity transformation of the Schrodinger equation, in which bound-state spectra are not changed but continuum spectra are separated into resonant and non-resonant continuum ones. Because the asymptotic wave functions of the separated resonant states are regularized by the CSM, many-body resonances can be obtained by solving an eigenvalue problem with the $L^2$ basis functions. Applying this method to a system consisting of a core and valence nucleons, we investigate many-body resonant states in weakly bound nuclei very far from the stability lines. Non-resonant continuum states are also obtained with the discretized eigenvalues on the rotated branch cuts. Using these complex eigenvalues and eigenstates in CSM, we construct the extended completeness relations and Greens functions to calculate strength functions and breakup cross sections. Various kinds of theoretical calculations and comparisons with experimental data are presented.
We examine the phenomenology of the production, at the 13 TeV Large Hadron Collider (LHC), of a heavy resonance $X$, which decays via other new on-shell particles $n$ into multi- (i.e. three or more) photon final states. In the limit that $n$ has a much smaller mass than $X$, the multi-photon final state may dominantly appear as a two photon final state because the $gamma$s from the $n$ decay are highly collinear and remain unresolved. We discuss how to discriminate this scenario from $X rightarrow gamma gamma$: rather than discarding non-isolated photons, it is better instead to relax the isolation criterion and instead form photon jet substructure variables. The spins of $X$ and $n$ leave their imprint upon the distribution of pseudorapidity gap $Delta eta$ between the apparent two photon states. Depending on the total integrated luminosity, this can be used in many cases to claim discrimination between the possible spin choices of $X$ and $n$, although the case where $X$ and $n$ are both scalar particles cannot be discriminated from the direct $X rightarrow gamma gamma$ decay in this manner. Information on the mass of $n$ can be gained by considering the mass of each photon jet.
This paper explores the physics reach of the proton-proton Future Circular Collider (FCC-hh) and of the High-Energy LHC (HE-LHC) for searches of new particles produced in the $s$-channel and decaying to two high-energy leptons, jets (non-tops), tops or W/Z bosons. We discuss the expected discovery potential and exclusion limits for benchmark models predicting new massive particles that result in resonant structures in the invariant mass spectrum. We also present a detailed study of the HE-LHC potential to discriminate among different models, for a $Z$ that could be discovered by the end of High-Luminosity LHC (HL-LHC).
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
