Infrared Renormalons and Power Suppressed Effects in e+e−e^+e^- Jet Events

We study the effect of infrared renormalons upon shape variables that are commonly used to determine the strong coupling constant in $e^+e^-$ annihilation into hadronic jets. We consider the model of QCD in the limit of large $n_f$. We find a wide variety of different behaviours of shape variables with respect to power suppressed effects induced by infrared renormalons. In particular, we find that oblateness is affected by $1/Q$ non--perturbative effects even away from the two jet region, and the energy--energy correlation is affected by $1/Q$ non--perturbative effects for all values of the angle. On the contrary, variables like thrust, the $c$ parameter, the heavy jet mass, and others, do not develop any $1/Q$ correction away from the two jet region at the leading $n_f$ level. We argue that $1/Q$ corrections will eventually arise at subleading $n_f$ level, but that they could maintain an extra \as(Q) suppression. We conjecture therefore that the leading power correction to shape variables will have in general the form $\alpha^n_{\rm S}(Q)/Q$, and it may therefore be possible to classify shape variables according to the value of $n$.Comment: 20 pages, Latex, epsfig, 3 tar-gzip-uuencoded figures. Also available from http://surya11.cern.ch/users/nason/misc

Nuclear magnetic resonance cryoporometry

Nuclear Magnetic Resonance (NMR) cryoporometry is a technique for non-destructively determining pore size distributions in porous media through the observation of the depressed melting point of a confined liquid. It is suitable for measuring pore diameters in the range 2 nm-1 mu m, depending on the absorbate. Whilst NMR cryoporometry is a perturbative measurement, the results are independent of spin interactions at the pore surface and so can offer direct measurements of pore volume as a function of pore diameter. Pore size distributions obtained with NMR cryoporometry have been shown to compare favourably with those from other methods such as gas adsorption, DSC thermoporosimetry, and SANS. The applications of NMR cryoporometry include studies of silica gels, bones, cements, rocks and many other porous materials. It is also possible to adapt the basic experiment to provide structural resolution in spatially-dependent pore size distributions, or behavioural information about the confined liquid

Characterisation of porous solids using small-angle scattering and NMR cryoporometry

The characteristics of several porous systems have been studied by the use of small-angle neutron scattering [SANS] and nuclear magnetic resonance [NMR] techniques. The measurements reveal different characteristics for sol-gel silicas, activated carbons and ordered mesoporous silicas of the MCM and SBA type. Good agreement is obtained between gas adsorption measurements and the NMR and SANS results for pore sizes above 10 nm. Recent measurements of the water/ice phase transformation in SBA silicas by neutron diffraction are also presented and indicate a complex relationship that will require more detailed treatment in terms of the possible effects of microporosity in the silica substrate. The complementarity of the different methods is emphasised and there is brief discussion of issues related to possible future developments

The Other Janus and the Future of Labor’s Capital

Two forms of labor’s capital—union funds and public pension funds— have profoundly reshaped the corporate world. They have successfully advocated for shareholder empowerment initiatives like proxy access, declassified boards, majority voting, say on pay, private fund registration, and the CEO-to-worker pay ratio. They have also served as lead plaintiffs in forty percent of federal securities fraud and Delaware deal class actions. Today, much-discussed reforms like revised shareholder proposal rules and mandatory arbitration threaten two of the main channels by which these shareholders have exercised power. But labor’s capital faces its greatest, even existential, threats from outside corporate law. This Essay addresses one of those threats: the direct and indirect challenges posed to labor’s capital by the Supreme Court’s holding in Janus v. American Federation of State, County, and Municipal Employees, Council 31. These threats may have spillover effects in the corporate arena. This Essay discusses these developments in light of Randall Thomas’s early and prescient work on labor as a shareholder

Is \u27Pay-to-Play\u27 Driving Public Pension Fund Activism in Securities Class Actions? An Empirical Study

The recent emergence of public pension funds as frequent lead plaintiffs in securities class actions has prompted speculation that the funds’ litigation activism is driven by “pay-to-play”. “Pay-to-play” posits that public pension funds are driven by politician board members to obtain lead plaintiff appointments in securities class actions because of campaign contributions made by plaintiffs’ lawyers to those board members. This paper provides a comprehensive analysis of the securities litigation activity of 111 such funds from the years 2003 through 2006. Three of the paper’s findings cast doubt on the “pay-to-play” theory, including that: (1) politicians and political control negatively correlate with lead plaintiff appointments; (2) beneficiary board members - and outright beneficiary control of the board - positively correlate with such appointments; and (3) the degree of a pension fund’s underfunding positively correlates with lead plaintiff appointments, particularly when the fund is controlled by beneficiaries. The substantial role played by beneficiary board members in driving the funds’ litigation activism is analyzed by the author in the context of prior literature comparing such board members to corporate managers with an equity stake in a corporation. The paper also finds no support for the theory that unions drive beneficiary board members to obtain lead plaintiff appointments, and offers evidence that resistance by politicians to lead plaintiff appointments correlates with the degree of business influence in the politicians’ home states

The Humanities Strike Back: (E)ESG and Justice Strine Challenge Gamer Shareholder Primacy

Leo E. Strine, Jr. is closing in on Blair and Stout for the undisputed title of all-time top-scoring stakeholderist.3 I don\u27t intend to squander this opportunity to roast and toast him by weighing the pros and cons of basketscoring primacy. Instead, my aim is to surface an overlooked argument in the debate over shareholder primacy and stakeholderism, the case for which has been recently reinvigorated by Strine\u27s work. My argument is this: one underappreciated aspect of shareholder primacy\u27s appeal is that it creates a competition with a single endpoint, basically a game, and that the exhilarating tournament that results, separate and apart from any ethical or instrumental justification, is an underestimated aspect of shareholder primacy\u27s appeal. I want to be clear that this is not intended as any glib insult hurled at the doctrine. Quite the contrary, its advocates root their claims in wholly legitimate philosophical foundations, in libertarian ideas about freedom and private property, in notions of the common good best advanced by each person pursuing his or her own lawful self-interest, in empirical claims about what best stimulates economic growth, in pragmatic claims that stakeholder interests are best addressed by governments, not corporations. 4 I disagree with some of these claims, but accept the good faith nature of the arguments made in their favor

Private Policing of Mergers & Acquisitions: An Empirical Assessment of Institutional Lead Plaintiffs in Transactional Class and Derivative Actions

Transactional class and derivative actions have long been controversial in both the popular and the academic literatures. Yet, the debate over such litigation has thus far neglected to consider a change in legal technology, adopted in Delaware a dozen years ago, favoring selection of institutional investors as lead plaintiffs in these cases. This Article fills that gap, offering new insights into the utility of mergers and acquisitions litigation. Based on a hand-collected dataset of all Delaware class and derivative actions filed from November 1, 2003 to December 31, 2009, I find that institutional investors play as large of a role in these cases as they do in federal securities fraud class actions, leading 41% of them. Controlling for the size of the deal and other factors, institutions have been more likely to assume a lead role in cases with lower premiums over the trading price, at least until the collapse of Lehman Brothers in September 2008, at which point most institutional types increased their litigation activity and sued in higher premium deals too. Other case and deal characteristics significantly predict institutional lead plaintiffs, such as the number of complaints filed in the case (an illustration of lead plaintiff competitiveness), the length of the complaint (a measure of attorney effort), whether the transaction is cash-for-stock, the market capitalization of the target, and the presence of Go-Shop provisions (which negatively correlate with institutional lead plaintiffs). I also find that public-pension funds, in particular, target controlling shareholder transactions. I present evidence that public-pension funds, alone among institutional types, statistically significantly correlate with the outcomes of greatest interest to shareholders — both an increase in the offer price and lower attorneys\u27 fees. The improvement in offer price associated with public-pension funds may be because they are better shareholder representatives. It may also be because they cherry-pick the best cases, although I offer some evidence against this hypothesis. These results are consistent with the view that public-pension funds outperform traditional lead plaintiffs as monitors of class counsel and that they reduce agency costs for shareholders in mergers-and-acquisitions litigation

Clathrate formation and dissociation in vapor/water/ice/hydrate systems in SBA-15, sol-gel and CPG porous media, as probed by NMR relaxation, novel protocol NMR cryoporometry, neutron scattering and ab initio quantum-mechanical molecular dynamics simulation

The Gibbs-Thomson effect modifies the pressure and temperature at which clathrates occur, hence altering the depth at which they occur in the seabed. Nuclear magnetic resonance (NMR) measurements as a function of temperature are being conducted for water/ice/ hydrate systems in a range of pore geometries, including templated SBA-15 silicas, controlled pore glasses and sol-gel silicas. Rotator-phase plastic ice is shown to be present in confined geometry, and bulk tetrahydrofuran hydrate is also shown to probably have a rotator phase. A novel NMR cryoporometry protocol, which probes both melting and freezing events while avoiding the usual problem of supercooling for the freezing event, has been developed. This enables a detailed probing of the system for a given pore size and geometry and the exploration of differences between hydrate formation and dissociation processes inside pores. These process differences have an important effect on the environment, as they impact on the ability of a marine hydrate system to re-form once warmed above a critical temperature. Ab initio quantum-mechanical molecular dynamics calculations are also being employed to probe the dynamics of liquids in pores at nanometric dimensions

Reconstructing particle masses from pairs of decay chains

A method is proposed for determining the masses of the new particles N,X,Y,Z in collider events containing a pair of effectively identical decay chains Z to Y+jet, Y to X+l_1, X to N+l_2, where l_1, l_2 are opposite-sign same-flavour charged leptons and N is invisible. By first determining the upper edge of the dilepton invariant mass spectrum, we reduce the problem to a curve for each event in the 3-dimensional space of mass-squared differences. The region through which most curves pass then determines the unknown masses. A statistical approach is applied to take account of mismeasurement of jet and missing momenta. The method is easily visualized and rather robust against combinatorial ambiguities and finite detector resolution. It can be successful even for small event samples, since it makes full use of the kinematical information from every event.Comment: 12 pages, 5 figure