Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userMore about on the mass of the new charmonium states
305
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
If the $X(3872)$ is described by the picture as a mixture of the charmonium and molecular $D^{ast} D$ states; $Y(3940)$ as a mixture of the $chi_{c0}$ and $D^ast D^ast$ states; and $X(4260)$ as a mixture of the tetra-quark and charmonium sates, their orthogonal combinations should also exist. We estimate the mass and residues of the states within the QCD sum rules method. We find that the mass splitting among $X$, $Y$ and their orthogonal states is at most $200MeV$. Experimental search of these new states can play critical role for establishing the nature of the new charmonium states.
rate research
Read More
We look for all weak bases that lead to texture zeroes in the quark mass matrices and contain a minimal number of parameters in the framework of the standard model. Since there are ten physical observables, namely, six nonvanishing quark masses, three mixing angles and one CP phase, the maximum number of texture zeroes in both quark sectors is altogether nine. The nine zero entries can only be distributed between the up- and down-quark sectors in matrix pairs with six and three texture zeroes or five and four texture zeroes. In the weak basis where a quark mass matrix is nonsingular and has six zeroes in one sector, we find that there are 54 matrices with three zeroes in the other sector, obtainable through right-handed weak basis transformations. It is also found that all pairs composed of a nonsingular matrix with five zeroes and a nonsingular and nondecoupled matrix with four zeroes simply correspond to a weak basis choice. Without any further assumptions, none of these pairs of up- and down-quark mass matrices has physical content. It is shown that all non-weak-basis pairs of quark mass matrices that contain nine zeroes are not compatible with current experimental data. The particular case of the so-called nearest-neighbour-interaction pattern is also discussed.
New results of the Belle experiment at the KEKB asymmetric e^+e^- collider are presented, in particular (a) measurement of the mass and width of the $eta_c$ and $eta_c$ in B meson decays, (b) measurement of the mass, width and quantum numbers of the X(3872) and (c) observation of the $chi_{c2}$ in $B$ meson decays.
In the past years there has been a revival of hadron spectroscopy. Many interesting new hadron states were discovered experimentally, some of which do not fit easily into the quark model. This situation motivated a vigorous theoretical activity. This is a rapidly evolving field with enormous amount of new experimental information. In the present report we include and discuss data which were released very recently. The present review is the first one written from the perspective of QCD sum rules (QCDSR), where we present the main steps of concrete calculations and compare the results with other approaches and with experimental data.
In this short review we present and discuss all the experimental information about the charged exotic charmonium states, which have been observed over the last five years. We try to understand their properties such as masses and decay widths with QCD sum rules. We describe this method, show the results and compare them with the experimental data and with other theoretical approaches.
We study moduli stabilization and a realization of de Sitter vacua in generalized F-term uplifting scenarios of the KKLT-type anti-de Sitter vacuum, where the uplifting sector X directly couples to the light Kahler modulus T in the superpotential through, e.g., stringy instanton effects. F-term uplifting can be achieved by a spontaneous supersymmetry breaking sector, e.g., the Polonyi model, the ORaifeartaigh model and the Intriligator-Seiberg-Shih model. Several models with the X-T mixing are examined and qualitative features in most models {it even with such mixing} are almost the same as those in the KKLT scenario. One of the quantitative changes, which are relevant to the phenomenology, is a larger hierarchy between the modulus mass m_T and the gravitino mass $m_{3/2}$, i.e., $m_T/m_{3/2} = {cal O}(a^2)$, where $a sim 4 pi^2$. In spite of such a large mass, the modulus F-term is suppressed not like $F^T = {cal O}(m_{3/2}/a^2)$, but like $F^T = {cal O}(m_{3/2}/a)$ for $ln (M_{Pl}/m_{3/2}) sim a$, because of an enhancement factor coming from the X-T mixing. Then we typically find a mirage-mediation pattern of gaugino masses of ${cal O}(m_{3/2}/a)$, while the scalar masses would be generically of ${cal O}(m_{3/2})$.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
