Lattice QCD study of a five-quark hadronic molecule

We compute the ground-state energies of a heavy-light K-Lambda like system as a function of the relative distance r of the hadrons. The heavy quarks, one in each hadron, are treated as static. Then, the energies give rise to an adiabatic potential Va(r) which we use to study the structure of the five-quark system. The simulation is based on an anisotropic and asymmetric lattice with Wilson fermions. Energies are extracted from spectral density functions obtained with the maximum entropy method. Our results are meant to give qualitative insight: Using the resulting adiabatic potential in a Schroedinger equation produces bound state wave functions which indicate that the ground state of the five-quark system resembles a hadronic molecule, whereas the first excited state, having a very small rms radius, is probably better described as a five-quark cluster, or a pentaquark. We hypothesize that an all light-quark pentaquark may not exist, but in the heavy-quark sector it might, albeit only as an excited state.Comment: 11 pages, 15 figures, 4 table

Consumers and Experts: An Econometric Analysis of the Demand for Water Heaters

Consumers can accumulate product information on the basis of a combination of searching, product advertising and expert advice.Examples of experts who provide product information include doctors advising patients on treatments, motor mechanics diagnosing car problems and recommending repairs, accountants recommending investment strategies, and plumbers making recommendations on alternative water heaters.In each of these examples, the transactions involve the sale of goods and services where the seller is at the same time an expert providing advice on the amount and type of product or service to be purchased.In the case of water heaters, the plumber advising a consumer on their choice of water heater will most likely also install the appliance.Because of the information asymmetry there is potentially a strategic element in the transmission of information from expert to consumer.This paper reports on an econometric investigation of the factors that determine the choices made by consumers and the recommendations made by plumbers and the extent to which plumbers act in the best interests of their customers.The empirical work is made possible by the availability of stated preference data generated by designed experiments involving separate samples of Australian consumers and plumbers.We find some evidence that plumbers have higher preferences than consumers for heater characteristics that increase their profit margin.consumers;demand;product information;advertising;investment;econometrics