ترغب بنشر مسار تعليمي؟ اضغط هنا

Impressions of the Meson Spectrum: Hybrids & Exotics, present and future

70   0   0.0 ( 0 )
 نشر من قبل Michael R. Pennington
 تاريخ النشر 2015
  مجال البحث
والبحث باللغة English
 تأليف M.R. Pennington




اسأل ChatGPT حول البحث

It has long been expected that the spectrum of hadrons in QCD would be far richer and extensive than experiment has so far revealed. While there have been experimental hints of this richness for some time, it is really only in the last few years that dramatic progress has been seen in the exploration both experimentally and in calculations on the lattice. Precision studies enabled by new technology both with detectors and high performance computations are converging on an understanding of the spectrum in strong coupling QCD. These methodologies are laying the foundation for a decade of potential discovery that electro and photoproduction experiments at Jefferson Lab, which when combined with key results on $B$ and charmonium decays from both $e^+e^-$ and $pp$ colliders, should turn mere impressions of the light meson spectrum into a high definition picture.

قيم البحث

اقرأ أيضاً

51 - Bengt Friman 1997
We study the $p$-wave polarization operator of the $rho$-meson due to $rho N$ interactions via the $N^*$ (1720) and $Delta (1905)$ resonances and compute the corresponding production rate for $e^+e^-$-pairs at finite temperature and baryon density. A t high baryon density we find a significant shift of the spectrum to lower invariant masses.
Discriminating hadronic molecular and multi-quark states is a long standing problem in hadronic physics. We propose here to utilize relativistic heavy ion collisions to resolve this problem, as exotic hadron yields are expected to be strongly affecte d by their structures. Using the coalescence model, we find that the exotic hadron yield relative to the statistical model result is typically an order of magnitude smaller for a compact multi-quark state, and larger by a factor of two or more for a loosely bound hadronic molecule. We further find that some of the newly proposed heavy exotic states could be produced and realistically measured at RHIC and LHC.
382 - Aurel Bulgac , Shi Jin , 2019
Recent developments in theoretical modeling and in computational power have allowed us to make significant progress on a goal not achieved yet in nuclear theory: a fully microscopic theory of nuclear fission. The complete microscopic description rema ins a computationally demanding task, but the information that can be provided by current calculations can be extremely useful to guide and constrain phenomenological approaches. First, a truly microscopic framework that can describe the real-time dynamics of the fissioning system can justify or rule out assumptions and approximations incompatible with an accurate quantum treatment or with our understanding of the inter nucleon interactions. Second, the microscopic approach can be used to obtain trends such as: the excitation energy sharing mechanism between fission fragments (FFs) with increasing excitation energy of the fissioning system, the angular momentum content of the FFs, or even to compute observables that cannot be otherwise calculated in phenomenological approaches or even measured, as in the case of astronomical environments. Merely the characterization of the trends would be of great importance for various application. We present here arguments that a truly microscopic approach to fission does not support the assumption of adiabaticity of the large amplitude collective motion in fission, particularly starting from the outer saddle down to the scission configuration.
58 - Q. Haider , L. C. Liu 2015
Eta-mesic nucleus or the quasibound nuclear state of an eta ($eta$) meson in a nucleus is caused by strong-interaction force alone. This new type of nuclear species, which extends the landscape of nuclear physics, has been extensively studied since i ts prediction in 1986. In this paper, we review and analyze in great detail the models of the fundamental $eta$--nucleon interaction leading to the formation of an $eta$--mesic nucleus, the methods used in calculating the properties of a bound $eta$, and the approaches employed in the interpretation of the pertinent experimental data. In view of the successful observation of the $eta$--mesic nucleus $^{25}$Mg$_{eta}$ and other promising experimental results, future direction in searching for more $eta$--mesic nuclei is suggested.
We present the results of an improved Monte Carlo Glauber (MCG) model of relevance for collisions involving nuclei at center-of-mass energies of BNL RHIC ($sqrt{s_{rm NN}}=0.2$ TeV), CERN LHC ($sqrt{s_{rm NN}}=2.76$-$8.8$ TeV), and proposed future ha dron colliders ($sqrt{s_{rm NN}}approx 10$-$63$ TeV). The inelastic pp cross sections as a function of $sqrt{s_{rm NN}}$ are obtained from a precise data-driven parametrization that exploits the many available measurements at LHC collision energies. We describe the nuclear transverse profile with two separated 2-parameter Fermi distributions for protons and neutrons to account for their different densities close to the nuclear periphery. Furthermore, we model the nucleon degrees of freedom inside the nucleus through a lattice with a minimum nodal separation, combined with a recentering and reweighting procedure, that overcomes some limitations of previous MCG approaches. The nuclear overlap function, number of participant nucleons and binary nucleon-nucleon collisions, participant eccentricity and triangularity, overlap area and average path length are presented in intervals of percentile centrality for lead-lead (PbPb) and proton-lead (pPb) collisions at all collision energies. We demonstrate for collisions at $sqrt{s_{rm NN}}=5.02$ TeV that the central values of the Glauber quantities change by up to 7%, in a few bins of reaction centrality, due to the improvements implemented, though typically remain within the previously assigned systematic uncertainties, while their associated uncertainties are generally smaller (mostly below 5%) at all centralities than for earlier calculations. Tables for all quantities versus centrality at present and foreseen collision energies involving Pb nuclei, as well as for collisions of XeXe at $sqrt{s_{rm NN}}=5.44$, and AuAu and CuCu at $sqrt{s_{rm NN}}=0.2$ TeV, are provided.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا