Production mechanisms and single-spin asymmetry for kaons in high energy hadron-hadron collisions

Direct consequences on kaon production of the picture proposed in a recent Letter and subsequent publications are discussed. Further evidence supporting the proposed picture is obtained. Comparison with the data for the inclusive cross sections in unpolarized reactions is made. Quantitative results for the left-right asymmetry in single-spin processes are presented.Comment: 10 pages, 2 Postscript figure

Lambda Polarization in Polarized Proton-Proton Collisions at RHIC

We discuss Lambda polarization in semi-inclusive proton-proton collisions, with one of the protons longitudinally polarized. The hyperfine interaction responsible for the $\Delta$-$N$ and $\Sigma$-$\Lambda$ mass splittings gives rise to flavor asymmetric fragmentation functions and to sizable polarized non-strange fragmentation functions. We predict large positive Lambda polarization in polarized proton-proton collisions at large rapidities of the produced Lambda, while other models, based on SU(3) flavor symmetric fragmentation functions, predict zero or negative Lambda polarization. The effect of $\Sigma^0$ and $\Sigma^*$ decays is also discussed. Forthcoming experiments at RHIC will be able to differentiate between these predictions.Comment: 18 pages, 5 figure

Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron collisions

We discuss Lambda polarization and single-spin left-right asymmetry in diffractive hadron-hadron scattering at high energies. We show that the physical picture proposed in a recent Letter is consistent with the experimental observation that $\Lambda$ polarization in the diffractive process, $pp\to \Lambda K^+p$, is much higher than that in the inclusive reaction, $pp\to \Lambda X$. We make predictions for the left-right asymmetry, A_N, and for the spin transfer, $D_{NN}^\Lambda$, in the single-spin process $p(\uparrow)p\to \Lambda K^+p$ and suggest further experimental tests of the proposed picture.Comment: 14 pages, 3 ps-figures. Phys. Rev. D (in press

Development of an optimized processing method for Withania frutescens

Withania somnifera (L.) Dunal originates mainly from Northern and Southern India. Primarily the roots are used in the Ayurvedic medicine as tonic, sedative hypnotic, adstringent, diuretic, emetic, and aphrodisiac. In Europe, it is widely used in food supplements. Due to the many effects and uses of this plant, the analysis of the Withania somnifera and optimization of industrial processing is nowadays an important issue. In Europe W. frutescens is native, and may be interesting for industrial preparation due to its similar phytochemical profile to W. somnifera. The point of our research was to develop an effective extraction and hydrolysis method of the Withania frutescens leaves to optimize the industrial processing

Single spin asymmetries in QCD

Measurements of single transverse spin asymmetries in high energy inclusive processes have always shown unexpected and challenging results. Several cases are considered and discussed within a QCD approach which couples perturbative dynamics to new non perturbative partonic information; the aim is that of developing a consistent phenomenological description of these unusual single spin phenomena, based on a generalized QCD factorization scheme.Comment: 14 pages, lectures delivered at School on "Symmetries and Spin", Praha-SPIN-2001, Prague, July 15 - July 28, 200

Tracing the origin of the single-spin asymmetries observed in inclusive hadron production processes at high energies

It is pointed out that the existing models for the left-right asymmetries observed in single-spin inclusive hadron production processes can be differentiated experimentally. Several such experiments are proposed with which the basic assumptions of these models can be tested individually.Comment: 12 pages, one figur

Analyzing powers in inclusive pion production at high energy and the nucleon spin structure

Analyzing powers in inclusive pion production in high energy transversely polarized proton-proton collisions are studied theoretically in the framework of the quark recombination model. Calculations by assuming the SU(6) spin-flavor symmetry for the nucleon structure disagree with the experiments. We solve this difficulty by taking into account the %We overcome this difficulty by taking into account the realistic spin distribution functions of the nucleon, which differs from the SU(6) expectation at large $x$, %but coincides with a perturbative QCD constraint on the ratio of the unpolarized valence distributions, $u/d \to 5$ as $x \to 1$. We also discuss the kaon spin asymmetry and find $A_N(K^+) = -A_N(K^0)$ in the polarized proton-proton collisions at large $x_F$.Comment: 13 pages, 4 figures, late

Upper and Lower Bounds for Weak Backdoor Set Detection

We obtain upper and lower bounds for running times of exponential time algorithms for the detection of weak backdoor sets of 3CNF formulas, considering various base classes. These results include (omitting polynomial factors), (i) a 4.54^k algorithm to detect whether there is a weak backdoor set of at most k variables into the class of Horn formulas; (ii) a 2.27^k algorithm to detect whether there is a weak backdoor set of at most k variables into the class of Krom formulas. These bounds improve an earlier known bound of 6^k. We also prove a 2^k lower bound for these problems, subject to the Strong Exponential Time Hypothesis.Comment: A short version will appear in the proceedings of the 16th International Conference on Theory and Applications of Satisfiability Testin

Game saturation of intersecting families

We consider the following combinatorial game: two players, Fast and Slow, claim $k$-element subsets of $[n]=\{1,2,...,n\}$ alternately, one at each turn, such that both players are allowed to pick sets that intersect all previously claimed subsets. The game ends when there does not exist any unclaimed $k$-subset that meets all already claimed sets. The score of the game is the number of sets claimed by the two players, the aim of Fast is to keep the score as low as possible, while the aim of Slow is to postpone the game's end as long as possible. The game saturation number is the score of the game when both players play according to an optimal strategy. To be precise we have to distinguish two cases depending on which player takes the first move. Let $gsat_F(\mathbb{I}_{n,k})$ and $gsat_S(\mathbb{I}_{n,k})$ denote the score of the saturation game when both players play according to an optimal strategy and the game starts with Fast's or Slow's move, respectively. We prove that $\Omega_k(n^{k/3-5}) \le gsat_F(\mathbb{I}_{n,k}),gsat_S(\mathbb{I}_{n,k}) \le O_k(n^{k-\sqrt{k}/2})$ holds

Single spin asymmetries in DIS

We consider possible mechanisms for single spin asymmetries in inclusive Deep Inelastic Scattering (DIS) processes with unpolarized leptons and transversely polarized nucleons. Tests for the effects of non-zero \bfk_\perp, for the properties of spin dependent quark fragmentations and for quark helicity conservation are suggested.Comment: 5 pages, LaTeX, no figures. Revised version, to be published in Phys. Rev. D. Some equations and statements added to clarify text and notation