Possible Explanations for the NuTeV Weinberg Angle Measurement

The NuTeV collaboration has made an independent determination of the Weinberg angle by measuring charged and neutral-current cross sections from neutrino and antineutrino DIS on iron. Their value differs by 3 standard deviations from that obtained from measurements at the Z pole. We review this experiment and assess various possible explanations for this result, both within the Standard Model ("old physics") and outside the Standard Model ("new physics").Comment: QCD Down Under Workshop, CSSM, Adelaide, Australia, Mar 10-19, 2004; 6 pages, 3 figs; updated references on QCD effect

Charge Symmetry Violation Corrections to Determination of the Weinberg Angle in Neutrino Reactions

We show that the correction to the Paschos-Wolfenstein relation associated with charge symmetry violation in the valence quark distributions is essentially model independent. It is proportional to a ratio of quark momenta that is independent of Q^2. This result provides a natural explanation of the surprisingly good agreement found between our earlier estimates within several different models. When applied to the recent NuTeV measurement, this effect significantly reduces the discrepancy with other determinations of the Weinberg angle.Comment: 7 pages, no figures; expanded discussion of N.ne.Z correction

Classification of non-indigenous species based on their impacts: Considerations for application in marine management

Assessment of the ecological and economic/societal impacts of the introduction of non-indigenous species (NIS) is one of the primary focus areas of bioinvasion science in terrestrial and aquatic environments, and is considered essential to management. A classification system of NIS, based on the magnitude of their environmental impacts, was recently proposed to assist management. Here, we consider the potential application of this classification scheme to the marine environment, and offer a complementary framework focussing on value sets in order to explicitly address marine management concerns. Since existing data on marine NIS impacts are scarce and successful marine removals are rare, we propose that management of marine NIS adopt a precautionary approach, which not only would emphasise preventing new incursions through pre-border and at-border controls but also should influence the categorisation of impacts. The study of marine invasion impacts requires urgent attention and significant investment, since we lack the luxury of waiting for the knowledge base to be acquired before the window of opportunity closes for feasible management

Can R-parity violation explain the LSND data as well?

The recent Super-Kamiokande data now admit only one type of mass hierarchy in a framework with three active and one sterile neutrinos. We show that neutrino masses and mixings generated by R-parity-violating couplings, with values within their experimental upper limits, are capable of reproducing this hierarchy, explaining all neutrino data particularly after including the LSND results.Comment: 7 pages, Latex, 3 PS figures; in v2 a few clarifying remarks included and two references added (to appear in Physical Review D

Supernova Bounds on Majoron-emitting decays of light neutrinos

Neutrino masses arising from the spontaneous violation of ungauged lepton-number are accompanied by a physical Goldstone boson, generically called Majoron. In the high-density supernova medium the effects of Majoron-emitting neutrino decays are important even if they are suppressed in vacuo by small neutrino masses and/or small off-diagonal couplings. We reconsider the influence of these decays on the neutrino signal of supernovae in the light of recent Super-Kamiokande data on solar and atmospheric neutrinos. We find that majoron-neutrino coupling constants in the range 3\times 10^{-7}\lsim g\lsim 2\times 10^{-5} or g \gsim 3 \times 10^{-4} are excluded by the observation of SN1987A. Then we discuss the potential of Superkamiokande and the Sudbury Neutrino Observatory to detect majoron neutrino interactions in the case of a future galactic supernova. We find that these experiments could probe majoron neutrino interactions with improved sensitivity.Comment: 28 pages, 5 figure

Valence-quark distributions in the pion

We calculate the pion's valence-quark momentum-fraction probability distribution using a Dyson-Schwinger equation model. Valence-quarks with an active mass of 0.30 GeV carry 71% of the pion's momentum at a resolving scale q_0=0.54 GeV = 1/(0.37 fm). The shape of the calculated distribution is characteristic of a strongly bound system and, evolved from q_0 to q=2 GeV, it yields first, second and third moments in agreement with lattice and phenomenological estimates, and valence-quarks carrying 49% of the pion's momentum. However, pointwise there is a discrepancy between our calculated distribution and that hitherto inferred from parametrisations of extant pion-nucleon Drell-Yan data.Comment: 8 pages, 3 figures, REVTEX, aps.sty, epsfig.sty, minor corrections, version to appear in PR

Perturbative and nonperturbative contributions to the strange quark asymmetry in the nucleon

There are two mechanisms for the generation of an asymmetry between the strange and anti-strange quark distributions in the nucleon: nonperturbative contributions originating from nucleons fluctuating into virtual baryon-meson pairs such as $\Lambda K$ and $\Sigma K$, and perturbative contributions arising from gluons splitting into strange and anti-strange quark pairs. While the nonperturbative contributions are dominant in the large-$x$ region, the perturbative contributions are more significant in the small-$x$ region. We calculate this asymmetry taking into account both nonperturbative and perturbative contributions, thus giving a more accurate evaluation of this asymmetry over the whole domain of $x$. We find that the perturbative contributions are generally a few times larger in magnitude than the nonperturbative contributions, which suggests that the best region to detect this asymmetry experimentally is in the region $0.02 < x < 0.03$. We find that the asymmetry may have more than one node, which is an effect that should be taken into account, e.g. for parameterizations of the strange and anti-strange quark distributions used in global analysis of parton distributions.Comment: 14 pages, 4 figures, figures comparing theoretical calculations with NNPDF global analysis added, accepted for publication in EPJ

Reassessment of the NuTeV determination of the Weinberg angle

In light of the recent discovery of the importance of the isovector EMC effect for the interpretation of the NuTeV determination of sin^2 theta_W, it seems timely to reassess the central value and the errors on this fundamental Standard Model parameter derived from the NuTeV data. We also include earlier work on charge symmetry violation and the recent limits on a possible asymmetry between s and \bar{s} quarks. With these corrections we find a revised NuTeV result of sin^2 theta_W = 0.2232 \pm 0.0013(stat) \pm 0.0024(syst), which is in excellent agreement with the running of sin^2 theta_W predicted by the Standard Model.Comment: 4 pages, one figur

Defects and glassy dynamics in solid He-4: Perspectives and current status

We review the anomalous behavior of solid He-4 at low temperatures with particular attention to the role of structural defects present in solid. The discussion centers around the possible role of two level systems and structural glassy components for inducing the observed anomalies. We propose that the origin of glassy behavior is due to the dynamics of defects like dislocations formed in He-4. Within the developed framework of glassy components in a solid, we give a summary of the results and predictions for the effects that cover the mechanical, thermodynamic, viscoelastic, and electro-elastic contributions of the glassy response of solid He-4. Our proposed glass model for solid He-4 has several implications: (1) The anomalous properties of He-4 can be accounted for by allowing defects to freeze out at lowest temperatures. The dynamics of solid He-4 is governed by glasslike (glassy) relaxation processes and the distribution of relaxation times varies significantly between different torsional oscillator, shear modulus, and dielectric function experiments. (2) Any defect freeze-out will be accompanied by thermodynamic signatures consistent with entropy contributions from defects. It follows that such entropy contribution is much smaller than the required superfluid fraction, yet it is sufficient to account for excess entropy at lowest temperatures. (3) We predict a Cole-Cole type relation between the real and imaginary part of the response functions for rotational and planar shear that is occurring due to the dynamics of defects. Similar results apply for other response functions. (4) Using the framework of glassy dynamics, we predict low-frequency yet to be measured electro-elastic features in defect rich He-4 crystals. These predictions allow one to directly test the ideas and very presence of glassy contributions in He-4.Comment: 33 pages, 13 figure

The Vehicle, Fall 2009

Table of Contents Poetry AliveRashelle McNairpage 3 Train of ThoughtsJeanette Saribekianpage 4 Biding the TideMarlee Lutzpage 5 Rotten HarvestJessyca Revillapage 15 Nostalgia ODJustine Fittonpage 16 Beyond WordsAshley Wrightpage 26 Don\u27tMelinda Knightpage 27 Happy HourStephen Garciapage 35 UntitledDaniel Paquinpage 37 Vibrant SensationsAshton Tembypage 38 Scarecrow Sally on a Saturday NightDaniel Davispage 45 The FarmAshley Wrightpage 49 Anything ButJustine Fittonpage 51 CrashDanielle Shirtinopage 53 Weathering SatisfactionRashelle McNairpage 54 SeminarDaniel Davispage 71 Nature\u27s Mood SwingsJeanette Saribekianpage 72 The PerformanceMelinda Knightpage 68 AmaterasuMarlee Lutzpage 82 Prose AirLauren Davidsonpage 6 The Twang of OrangesJ.T. Dawsonpage 18 ListenStephani Pescitellipage 29 The Rise and Fall of NickNickolas Alexanderpage 30 LossSimyona Deanovapage 39 Like DiamondsMark Rheaumepage 42 Moral FixationBryan Rolfsenpage 47 Reflections in College AlgebraNicole Reichertpage 52 LeashDaniel Paquinpage 56 I Lost My KeysJustine Fittonpage 75 A Third Grade EssayMark Rheaumepage 69 Be Careful, They BiteDaniel Davispage 84 Art Limb BurgAlycia Rockeycover AvesSamantha Flowerspage 14 Life-LuminescenceStephani Pescitellipage 25 MonopolyMegan Mathypage 28 Carousel NostalgiaAlycia Rockeypage 36 ShoesSarah Olsonpage 41 Waimea BayJarrod Taylorpage 50 Peacock Plumage Alycia Rockeypage 55 Building a HouseStephani Pescitellipage 70 ShellMegan Mathypage 74 From the VacationSamantha Flowerspage 73 Chicago CanopyAlycia Rockeypage 83 Features Editor\u27s NoteLindsey Durbinpage 1 LazarusDr. David Radavichpage 2 James K. Johnson Creative Writing Awardpage 88 Winning Entries (Poetry)Matthew J. Schumakepage 89 Winning Entry (Nonfiction)Jennifer O\u27Neilpage 92 Interview, 2009 Chapbook WinnerDaniel Davispage 95 Contributorspage 99https://thekeep.eiu.edu/vehicle/1090/thumbnail.jp