Trial by Fire: Major-General Christopher Vokes at the Battles of the Moro River and Ortona, December 1943

During the month of December 1943, the 1st Canadian Infantry Division (1st Cdn Div) underwent the most severe trial yet experienced by Canadian troops in Italy, when it crossed the Moro River, engaged two German divisions in rapid succession and, after a week of vicious street fighting, took the town of Ortona. Hailed at the time as victories, these battles have since been the subject of considerable debate among soldiers and historians alike. Much of the controversy has revolved around the division’s commander, Major-General Christopher Vokes, who has been accused by some of mishandling his formation, and has been castigated by others for the heavy cost in lives that resulted.1 Are these verdicts too harsh? Was he solely to blame for the manner in which the battles of the Moro River and Ortona evolved, and for their tragic cost? In order to better understand Chris Vokes’ actions during his first divisional battle, it will be argued that he did indeed make mistakes but at the same time was forced to deal with an extremely difficult set of circumstances that largely dictated the course and outcome of the battle. These included a strategic situation that created the conditions for a war of attrition; an unrealistic Army Grouplevel plan; unfavourable terrain and weather; unexpected changes in German defensive tactics; the “fog of war”; and his own inexperience as a divisional commander. As a result Vokes faced the toughest challenge of his military career

Quark mixing from softly broken symmetries

Quark flavor mixing may originate in the soft breaking of horizontal symmetries. Those symmetries, which in the simplest case are three family U(1) groups, are obeyed only by the dimension-4 Yukawa couplings and lead, when unbroken, to the absence of mixing. Their breaking may arise from the dimension-3 mass terms of SU(2)-singlet vector-like quarks. Those gauge-singlet mass terms break the horizontal symmetries at a scale much higher than the Fermi scale, yet softly, leading to quark mixing while the quark masses remain unsuppressed.Comment: 9 pages, plain Latex, no figure

Chirally improving Wilson fermions - I. O(a) improvement

We show that it is possible to improve the chiral behaviour and the approach to the continuum limit of correlation functions in lattice QCD with Wilson fermions by taking arithmetic averages of correlators computed in theories regularized with Wilson terms of opposite sign. Improved hadronic masses and matrix elements can be obtained by similarly averaging the corresponding physical quantities separately computed within the two regularizations. To deal with the problems related to the spectrum of the Wilson--Dirac operator, which are particularly worrisome when Wilson and mass terms are such as to give contributions of opposite sign to the real part of the eigenvalues, we propose to use twisted-mass lattice QCD for the actual computation of the quantities taking part to the averages. The choice $\pm \pi/2$ for the twisting angle is particularly interesting, as O($a$) improved estimates of physical quantities can be obtained even without averaging data from lattice formulations with opposite Wilson terms. In all cases little or no extra computing power is necessary, compared to simulations with standard Wilson fermions or twisted-mass lattice QCD.Comment: 71 pages, Latex, Keywords: Lattice, Improvement, Chirality. Version v2: mistake corrected in transformation properties under \omega -> -\omega, sect. 5.3.1 (see also sect. 6.1). Minor corrections in App. D and argument clarified in App. F. Version v3: minor modifications in sect. 2 (pag. 8-10: on the odd r-parity of M_crit(r)), in sect. 3.1.3 and 5.4.1 (few sentences about cutoff effects at small quark mass) and in sect. 3.2 (details of discussion below eq. 3.17); updated/added some reference

Two versions of the tragedy of the commons

D62, D72, Externalities, Tragedy of the commons, Cost sharing, Surplus sharing, Average cost, Average return,