Overview of the Tevatron Collider Complex: Goals, Operations and Performance

For more than two decades the Tevatron proton-antiproton collider was the centerpiece of the world's high energy physics program. The collider was arguably one of the most complex research instruments ever to reach the operation stage and is widely recognized for numerous physics discoveries and for many technological breakthroughs. In this article we outline the historical background that led to the construction of the Tevatron Collider, the strategy applied to evolution of performance goals over the Tevatron's operational history, and briefly describe operations of each accelerator in the chain and achieved performance.Comment: Includes modifications suggested by reviewer

Dijet Production at Large Rapidity Intervals

We examine dijet production at large rapidity intervals at Tevatron energies, by using the theory of Lipatov and collaborators which resums the leading powers of the rapidity interval. We analyze the growth of the Mueller-Navelet $K$-factor in this context and find it to be negligible. However, we do find a considerable enhancement of jet production at large transverse momenta. In addition, we show that the correlation in transverse momentum and azimuthal angle of the tagging jets fades away as the rapidity interval is increased.Comment: 12 pages, preprint DESY 93-139, SCIPP 93/3

Classical sum rules and spin correlations in photoabsorption and photoproduction processes

In this paper we study the possibility of generalizing the classical photoabsorption ($\gamma a \to b c$) sum rules, to processes $b c \to \gamma a$ and crossed helicity amplitudes. In the first case, using detailed balance, the sum rule is written as $\int_{\nu_{th}}^\infty {\frac{{d\nu}}{\nu}} K\Delta \sigma_{Born} (\nu)=0$ where $K$ is a kinematical constant which depends only on the mass of the particles and the center of mass energy. For other crossed helicity amplitudes, we show that there is a range of values of $s$ and $t$ for which the differential cross section for the process $\gamma b \to a c$ or $a c \to \gamma b$ in which the helicities of the photon and particle $a$ have specific values, is equal to the differential cross section for the process in which one of these two helicities is reversed (parallel-antiparallel spin correlation).Comment: 9 pages, 2 figure

Psychological Health and Smoking in Young Adulthood

Introduction: Young adulthood is a critical time for the emergence of risk behaviors including smoking. Psychological health is associated with smoking, but studies rarely track both over time. We used longitudinal data to assess whether average patterns of psychological health influenced average patterns of smoking and whether short-term fluctuations in psychological health influenced fluctuations in smoking. Method: Young adults aged 18–30 from the Panel Study of Income Dynamics were followed from 2007 to 2013, and mean trajectories of smoking were modeled. Psychological health variables included ever having a mental health diagnosis and time-varying distress. Results: In regression models, individuals with poorer psychological health (higher distress or a diagnosis) were more likely to be smokers and to smoke greater number of cigarettes. The association of diagnosis with number of cigarettes smoked increased with age. Conclusions: Smoking-related interventions should target individuals with poorer psychological health, even if they have no formal mental health diagnosis

One-loop helicity amplitudes for H -> gluons: the all-minus configuration

We use twistor inspired rules to compute the one-loop amplitude for a Higgs boson coupling to any number of negative helicity gluons in the large top mass limit.Comment: 5 pages, talk given at the conference "Loops and Legs in Quantum Field Theory", Eisenach, Germany, April 2006. Corrected typo

Depression and anxiety in sterilised women in Iran

Sterilisation is an effective and convenient means of contraception and has become increasingly popular as a birth control technique throughout the world during the past 40 years. However some women who choose sterilisation may suffer a neurotic syndrome, which is manifested in the form of pain, depression and loss of libido.1We undertook a study designed to investigate depression, anxiety and post-operation regret rate in sterilised women referred to health centres in Tabriz, Iran in 2006. The study design was descriptive-analytical. The study participants comprised 300 women in the age range 25–45 years, of whom 150 women were sterilized between 1 and 10 years ago and 150 were a control group of non-sterilised women who used condoms, withdrawal or safe period methods for contraception. The control group was selected by a cluster random sampling method. Fifteen health centres were selected as a cluster from 96 health centres located in Tabriz. Ten women were selected randomly from each health centre using health documents. Women were eligible for inclusion in the study if they were aged between 25 and 45 years at the time of sampling, and if they had no history of psychological disorders and no recent sorrowful events. There were no differences between the two groups as regards the number of children, income or demographic characteristics. The women were contacted by telephone at their last known address and were asked to complete questionnaires. Data collection was done using Zung’s self-rating depression and anxiety scale in addition to questions about post-sterilisation regret. Data were collected from the subjects anonymously and analysed using SPSS (v. 11.5) statistics software. Analysis employed t-test, Chi-square test and descriptive statistics. The comparison of the means for depression in the two groups was not significantly different (p = 0.96), however the mean of anxiety in the case group was remarkably greater than the control group (p = 0.03). Insufficient poststerilisation rest was a significant risk factor for depression and anxiety (p = 0.008 and p = 0.02, respectively). Requesting information about reversal after tubal sterilisation was 2.7% and the post-sterilisation regret rate was 6%, which was significantly related to women’s conflict with their husbands about the decision-making process prior to sterilisation (p<0.001). The study findings as regards psychological disorders of sterilisation suggested that women undergoing sterilisation should ensure that they have a good rest after their operation in order to reduce the extent of psychological disorders. Unlike studies undertaken in other countries,2–4 women’s age, parity, marriage duration and the timing of sterilisation was unrelated to the women’s regret in our study. The earlier the sterilisation is carried out, the longer the woman’s remaining period of fertile life and the greater the chances of changes in her marital status and/or the loss of a child, both circumstances that may lead to a change in the desired family size and expression of regret. In our study, probably one of the reasons why women’s regret did not appear to be significantly related to young age of sterilisation was the infrequency of divorce or remarriage in our study population. Consistent with our study, Jamieson et al. reported that women who had substantial conflict with their husbands or partners prior to sterilisation were more than three times as likely to regret their decision and more than five times more likely to request a reversal than women who did not report such conflict.5 In our study, pre-sterilisation counseling was reported by 29.3% of subjects. With respect to personality and adaptability differences in facing the changes, pre-sterilisation counseling and post-sterilisation follow-up systems have an important role to play in women’s psychological and psychosexual health promotion

Attitudes towards potential new tobacco control regulations among U.S. adults

Favorable attitudes towards tobacco control policies can facilitate their implementation and success. We examined attitudes toward four potential U.S. Federal tobacco regulations (banning menthol from cigarettes, reducing nicotine levels in cigarettes, banning candy and fruit flavored electronic cigarettes, and banning candy and fruit flavored little cigars and cigarillos) and associations with individual and state variables. A nationally representative phone survey of 4337 adults assessed attitudes toward potential policies. Weighted logistic regression was used to assess relationships between attitudes and demographic factors, smoking behavior, beliefs about the government (knowledge, trust, and credibility), exposure to tobacco control campaigns, and state variables from the US Centers for Disease Control and Prevention (CDC) State Tobacco Activities Tracking and Evaluation (STATE) System. Most respondents supported three out of four policies. Respondents that were female, non-white, Latino, living below the poverty line, had less than high school education, were of older age, did not smoke, had higher trust in government, and were exposed to national tobacco control campaigns had higher odds of expressing favorable attitudes toward potential new tobacco regulations than did their counterparts. No state-level effects were found. While differences in attitudes were observed by individual demographic characteristics, behaviors, and beliefs, a majority of participants supported most of the potential new tobacco regulations surveyed

Should the legal age for tobacco be raised? Results from a national sample of adolescents

Raising the minimum age of legal access to tobacco products may reduce smoking initiation and save lives. In a national telephone survey (2014-2015), US adolescents aged 13 to 17 years (N = 1,125; response rate, 66%) were asked about raising the age of legal access to tobacco products and randomized to hear one of 3 ages (19, 20, or 21 y). Most adolescents, across all US regions, favored raising the minimum age of legal access to 19 (75.7%), 20 (80.6%), or 21 (76.4%). These supportive attitudes may be useful to tobacco prevention and control practitioners who seek to reduce tobacco use among adolescents

Photon Spectrum Produced by the Late Decay of a Cosmic Neutrino Background

We obtain the photon spectrum induced by a cosmic background of unstable neutrinos. We study the spectrum in a variety of cosmological scenarios and also we allow for the neutrinos having a momentum distribution (only a critical matter dominated universe and neutrinos at rest have been considered until now). Our results can be helpful when extracting bounds on neutrino electric and magnetic moments from cosmic photon background observations.Comment: RevTex, 14 pages, 3 figures; minor changes, references added. To appear in Phys. Rev.

Hole Dispersions for Antiferromagnetic Spin-1/2 Two-Leg Ladders by Self-Similar Continuous Unitary Transformations

The hole-doped antiferromagnetic spin-1/2 two-leg ladder is an important model system for the high-$T_c$ superconductors based on cuprates. Using the technique of self-similar continuous unitary transformations we derive effective Hamiltonians for the charge motion in these ladders. The key advantage of this technique is that it provides effective models explicitly in the thermodynamic limit. A real space restriction of the generator of the transformation allows us to explore the experimentally relevant parameter space. From the effective Hamiltonians we calculate the dispersions for single holes. Further calculations will enable the calculation of the interaction of two holes so that a handle of Cooper pair formation is within reach.Comment: 16 pages, 26 figure