13,517 research outputs found
Radial Scaling in Inclusive Jet Production at Hadron Colliders
Inclusive jet production in p-p and pbar-p collisions shows many of the same
kinematic systematics as observed in single particle inclusive production at
much lower energies. In an earlier study (1974) a phenomenology, called radial
scaling, was developed for the single particle inclusive cross sections that
attempted to capture the essential underlying physics of point-like parton
scattering and the fragmentation of partons into hadrons suppressed by the
kinematic boundary. The phenomenology was successful in emphasizing the
underlying systematics of the inclusive particle productions. Here we
demonstrate that inclusive jet production at the LHC in high-energy p-p
collisions and at the Tevatron in pbar-p inelastic scattering show similar
behavior. The ATLAS inclusive jet production plotted as a function of this
scaling variable is studied for sqrt(s) of 2.76, 7 and 13 TeV and is compared
to pbar-p inclusive jet production at 1.96 TeV measured at the CDF and D0 at
the Tevatron and p-Pb inclusive jet production at the LHC ATLAS at sqrt(sNN) =
5.02 TeV. Inclusive single particle production at FNAL fixed target and ISR
energies are compared to inclusive J/Psi production at the LHC measured in
ATLAS, CMS and LHCb. Striking common features of the data are discussed.Comment: 47 pages, 22 figures, 6 tables. Version 2 - more data added,
references enhance
Tabled Labels: Consumers Eat Blind While Congress Feasts on Campaign Cash
As the Senate prepared to vote on its version of the U.S. Department of Agriculture's (USDA) budget, Public Citizen released an investigation to illustrate how big agribusiness used millions of dollars in lobbying expenditures and campaign contributions, and a network of Washington insiders with close connections to the Bush administration and Congress, to thwart a consumer-friendly provision mandating country-of-origin labeling, popularly known as COOL.Mandatory country-of-origin labeling would require beef, pork, lamb, fresh and frozen fruits and vegetables, fish, and peanuts to be labeled with where they were raised, grown or produced. Although the 2002 Farm Bill stipulated that the new program be implemented by September 2004, mandatory COOL has been postponed by Congress -- where lawmakers are under intense pressure from the meat and grocery industries -- for two years. In June, the U.S. House of Representatives voted to once again delay COOL's implementation for meat until 2007. Industry is strongly lobbying the Senate to either delay the funding for the USDA to work on COOL or turn it into a "voluntary" program.Public Citizen analyzed donations from 19 companies and trade associations, each of which has announced opposition to mandatory country-of-origin labeling and has registered to lobby against COOL. They have contributed a total of $12.6 million to candidates for Congress and in soft money to the Republican and Democratic parties since 2000.These companies have focused their giving on 64 members of Congress who have sponsored a bill to replace the mandatory country-of-origin requirement with a voluntary one, which is considerably weaker and does not empower consumers with the right to know where their food is from. Instead, it offers industry a way to hide critical information from the public. These 64 members, accounting for only 12 percent of Congress, have received 28 percent of contributions to candidates from the COOL foes
Demography and the tragedy of the commons
Individual success in group-structured populations has two components. First,
an individual gains by outcompeting its neighbors for local resources. Second,
an individual's share of group success must be weighted by the total
productivity of the group. The essence of sociality arises from the tension
between selfish gains against neighbors and the associated loss that
selfishness imposes by degrading the efficiency of the group. Without some
force to modulate selfishness, the natural tendencies of self interest
typically degrade group performance to the detriment of all. This is the
tragedy of the commons. Kin selection provides the most widely discussed way in
which the tragedy is overcome in biology. Kin selection arises from behavioral
associations within groups caused either by genetical kinship or by other
processes that correlate the behaviors of group members. Here, I emphasize
demography as a second factor that may also modulate the tragedy of the commons
and favor cooperative integration of groups. Each act of selfishness or
cooperation in a group often influences group survival and fecundity over many
subsequent generations. For example, a cooperative act early in the growth
cycle of a colony may enhance the future size and survival of the colony. This
time-dependent benefit can greatly increase the degree of cooperation favored
by natural selection, providing another way in which to overcome the tragedy of
the commons and enhance the integration of group behavior. I conclude that
analyses of sociality must account for both the behavioral associations of kin
selection theory and the demographic consequences of life history theory
A general model of the public goods dilemma
An individually costly act that benefits all group members is a public good.
Natural selection favors individual contribution to public goods only when some
benefit to the individual offsets the cost of contribution. Problems of sex
ratio, parasite virulence, microbial metabolism, punishment of noncooperators,
and nearly all aspects of sociality have been analyzed as public goods shaped
by kin and group selection. Here, I develop two general aspects of the public
goods problem that have received relatively little attention. First, variation
in individual resources favors selfish individuals to vary their allocation to
public goods. Those individuals better endowed contribute their excess
resources to public benefit, whereas those individuals with fewer resources
contribute less to the public good. Thus, purely selfish behavior causes
individuals to stratify into upper classes that contribute greatly to public
benefit and social cohesion and to lower classes that contribute little to the
public good. Second, if group success absolutely requires production of the
public good, then the pressure favoring production is relatively high. By
contrast, if group success depends weakly on the public good, then the pressure
favoring production is relatively weak. Stated in this way, it is obvious that
the role of baseline success is important. However, discussions of public goods
problems sometimes fail to emphasize this point sufficiently. The models here
suggest simple tests for the roles of resource variation and baseline success.
Given the widespread importance of public goods, better models and tests would
greatly deepen our understanding of many processes in biology and sociality
World city formation and long-distance communication under conditions of contemporary globalization : an empirical investigation of the relationship between air traffic and global service connectivity
Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at √s = 8 TeV with the ATLAS detector
Searches for the electroweak production of charginos, neutralinos and sleptons in final states characterized by the presence of two leptons (electrons and muons) and missing transverse momentum are performed using 20.3 fb[superscript −1] of proton-proton collision data at √s = 8 TeV recorded with the ATLAS experiment at the Large Hadron Collider. No significant excess beyond Standard Model expectations is observed. Limits are set on the masses of the lightest chargino, next-to-lightest neutralino and sleptons for different lightest-neutralino mass hypotheses in simplified models. Results are also interpreted in various scenarios of the phenomenological Minimal Supersymmetric Standard Model.United States. Dept. of EnergyNational Science Foundation (U.S.)Brookhaven National Laborator
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