Heavy Quarkonium Potential Model and the 1P1{}^1P_1 State of Charmonium

A theoretical explanation of the observed splittings among the P~states of charmonium is given with the use of a nonsingular potential model for heavy quarkonia. We also show that the recently observed mass difference between the center of gravity of the ${}^3P_J$ states and the ${}^1P_1$ state of $c\bar{c}$ does not provide a direct test of the color hyperfine interaction in heavy quarkonia. Our theoretical value for the mass of the ${}^1P_1$ state is in agreement with the experimental result, and its E1 transition width is 341.8~keV. The mass of the $\eta_c'$ state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen

On strong proximinality in normed linear spaces

The paper deals with strong proximinality in normed linear spaces. It is proved that in  a compactly locally uniformly rotund Banach space, proximinality, strong proximinality, weak approximative compactness and  approximative compactness are all equivalent for closed convex sets. How strong proximinality can be transmitted to and from quotient spaces has also been discussed

Expansion Aspect of Color Transparency on the Lattice

The opportunity to observe color transparency (CT) is determined by how rapidly a small-sized hadronic wave packet expands. Here we use SU(2) lattice gauge theory with Wilson fermions in the quenched approximation to investigate the expansion. The wave packet is modeled by a point hadronic source, often used as an interpolating field in lattice calculations. The procedure is to determine the Euclidean time (t), pion channel, Bethe-Salpeter amplitude $\Psi(r,t)$, and then evaluate $b^2(t)=\int d^3 r \Psi(r,t) r^2 sin^2 \theta \Psi_{\pi}(r)$. This quantity represents the soft interaction of a small-sized wave packet with a pion. The time dependence of $b^2(t)$ is fit as a superposition of three states, which is found sufficient to reproduce a reduced size wave packet. Using this superposition allows us to make the analytic continuation required to study the wave packet expansion in real time. We find that the matrix elements of the soft interaction $\hat b^2$ between the excited and ground state decrease rapidly with the energy of the excited state.Comment: 19 pages, latex, 4 figure

Chi_1 and Polarisation Asymmetries for Quarkonia at High Orders in Non-relativistic QCD

We study doubly polarised asymmetries of c-cbar and b-bbar mesons in hadro- and photo-production at low transverse momentum in non-relativistic QCD to high orders in the relative velocity of the pair, v. We give the complete set of expressions required for the asymmetries up to order v^9. The asymmetries in the production of eta_{c,b} states are a stable measure of the polarised gluon densities. The asymmetries for chi_{c,b}, J/psi, psi', and the various Upsilon states are stringent tests of the NRQCD scaling relations.Comment: 21 pages LaTeX including 2 figure

Stakeholder engagement strategies, national institutions, and firm performance: A configurational perspective

**Research summary** Research documents the performance effects of attending to shareholders and treating employees well but underplays national differences in the relative power of labor and capital. We advance a configurational perspective that acknowledges the fit between stakeholder engagement, context, firm attributes and performance. As a cornerstone of this perspective, we develop a typology of stakeholder engagement strategies expressing how firms navigate the tension between conforming with local expectations—by prioritizing shareholders or employees, according to context—and being distinctive—by diverging from their peers. Analyzing a cross‐national sample of firms from 2004 to 2011, we identify combinations of engagement strategies, firm attributes, and contexts linked to high performance. Our findings highlight the multiple context‐dependent paths, which link stakeholder engagement to high firm performance. **Managerial summary** How do firms navigate pressures from shareholders and employees across different institutional environments? We develop a typology of stakeholder engagement strategies based on how firms in different countries strike a balance between conformity (i.e., prioritizing locally important stakeholders) and differentiation (i.e., prioritizing stakeholders that their local peers might neglect). Our findings show that the engagement strategies associated with high performance vary according to local institutional context and firm characteristics. In particular, by not merely prioritizing stakeholders who are already locally important, firms can use stakeholder engagement to differentiate themselves from their peers, and such engagement strategies are often linked to high performance. **Online appendix: Data Set** Available at [https://doi.org/10.35065/sten-2001](https://doi.org/10.35065/sten-2001