The single inclusive spectrum of charged particles with transverse momenta
p
T
= 3 – 150 GeV/
c
measured at midrapidity by the CDF experiment in proton-antiproton
collisions at
is compared to ...next-to-leading order (NLO) perturbative QCD calculations using the most recent parametrizations of the parton distributions and parton-to-hadron fragmentation functions. Above
p
T
≈ 20 GeV/
c
, there is a very sizeable disagreement of the Tevatron data compared to the NLO predictions and to
x
T
-scaling expectations, suggesting a problem in the experimental data. We also present the predictions for the
p
T
-differential charged hadron spectra and the associated theoretical uncertainties for proton-proton (
p
-
p
) collisions at LHC energies
. Two procedures to estimate the charged hadron spectra at LHC heavy-ion collision energies
, 5.5 TeV) from
p
-
p
measurements are suggested.
Integrated approaches that expedite the production and processing of graphene into useful structures and devices, particularly through simple and environmentally friendly strategies, are highly ...desirable in the efforts to implement this two-dimensional material in state-of-the-art electrochemical energy storage technologies. Here, we introduce natural nucleotides (e.g., adenosine monophosphate) as bifunctional agents for the electrochemical exfoliation and dispersion of graphene nanosheets in water. Acting both as exfoliating electrolytes and colloidal stabilizers, these biomolecules facilitated access to aqueous graphene bio-inks that could be readily processed into aerogels and inkjet-printed interdigitated patterns. Na-O
batteries assembled with the graphene-derived aerogels as the cathode and a glyme-based electrolyte exhibited a full discharge capacity of ∼3.8 mAh cm
at a current density of 0.2 mA cm
. Moreover, shallow cycling experiments (0.5 mAh cm
) boasted a capacity retention of 94% after 50 cycles, which outperformed the cycle life of prior graphene-based cathodes for this type of battery. The positive effect of the nucleotide-adsorbed nanosheets on the battery performance is discussed and related to the presence of the phosphate group in these biomolecules. Microsupercapacitors made from the interdigitated graphene patterns as the electrodes also displayed a competitive performance, affording areal and volumetric energy densities of 0.03 μWh cm
and 1.2 mWh cm
at power densities of 0.003 mW cm
and 0.1 W cm
, respectively. Taken together, by offering a green and straightforward route to different types of functional graphene-based materials, the present results are expected to ease the development of novel energy storage technologies that exploit the attractions of graphene.
The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and ...inclusive charged particle production at central rapidities (eta<0.35) with respect to the reaction plane defined at high rapidities (eta=3-4 ). We observe that the v(2) of mesons falls below that of (anti)baryons for p(T)>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.
The relative abundance of the three decay modes B 0 → D − K + , B 0 → D − π + , and B 0 s → D − s π + produced in 7 TeV p p collisions at the LHC is determined from data corresponding to an ...integrated luminosity of 35 pb − 1 . The branching fraction of B 0 → D − K + is found to be B ( B 0 → D − K + ) = ( 2.01 ± 0.18 stat ± 0.14 syst ) × 10 − 4 . The ratio of fragmentation fractions f s / f d is determined through the relative abundance of B 0 s → D − s π + to B 0 → D − K + and B 0 → D − π + , leading to f s / f d = 0.253 ± 0.017 ± 0.017 ± 0.020 , where the uncertainties are statistical, systematic, and theoretical, respectively.
The PHENIX experiment has measured midrapidity transverse momentum spectra (0.4<p(T)<4.0 GeV/c) of single electrons as a function of centrality in Au+Au collisions at roots(NN) = 200 GeV. ...Contributions from photon conversions and Dalitz decays of light neutral mesons are measured by introducing a thin (1.7% X-0) converter into the PHENIX acceptance and are statistically removed. The subtracted nonphotonic electron spectra are primarily due to the semileptonic decays of hadrons containing heavy quarks, mainly charm at lower p(T). For all centralities, the charm production cross section is found to scale with the nuclear overlap function, T-AA. For minimum-bias collisions the charm cross section per binary collision is N-c (c) over bar/T-AA=622+/-57(stat)+/-160(syst) mub.
A search is performed for the lepton number violating decay B + → h − μ + μ + , where h − represents a K − or a π − , using an integrated luminosity of 36 pb − 1 of data collected with the LHCb ...detector. The decay is forbidden in the standard model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of B ( B + → K − μ + μ + ) < 5.4 × 10 − 8 and B ( B + → π − μ + μ + ) < 5.8 × 10 − 8 are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively.
A search is performed for the lepton number violating decay B + → h − μ + μ + , where h − represents a K − or a π − , using an integrated luminosity of 36 pb − 1 of data collected with the LHCb ...detector. The decay is forbidden in the standard model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of B ( B + → K − μ + μ + ) < 5.4 × 10 − 8 and B ( B + → π − μ + μ + ) < 5.8 × 10 − 8 are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively.
We discuss the physics of large impact parameter interactions at the LHC: ultraperipheral collisions (UPCs). The dominant processes in UPCs are photon–nucleon (nucleus) interactions. The current LHC ...detector configurations can explore hard phenomena at small
x
with nuclei and nucleons at photon–nucleon center-of-mass energies above 1 TeV, extending the
x
range of HERA by a factor of ten. In particular, it will be possible to probe diffractive and inclusive parton densities in nuclei using several processes. The interaction of small dipoles with protons and nuclei can be investigated in elastic and quasi-elastic
J
/
ψ
and
Υ
production as well as in high
t
ρ
0
production accompanied by a rapidity gap. Several of these phenomena provide clean signatures of the onset of the new high gluon density QCD regime. The LHC is in the kinematic range where nonlinear effects are several times larger than those at HERA. Two-photon processes in UPCs are also studied. In addition, while UPCs play a role in limiting the maximum beam luminosity, they can also be used as a luminosity monitor by measuring mutual electromagnetic dissociation of the beam nuclei. We also review similar studies at HERA and RHIC as well as describe the potential use of the LHC detectors for UPC measurements.
Transverse momentum spectra for charged hadrons and for neutral pions in the range 1 Gev/c < P-T < 5 GeV/c have been measured by the PHENIX experiment at RHIC in Au + Au collisions at rootS(NN) = 130 ...GeV. At high p(T) the spectra from peripheral nuclear collisions are consistent with scaling the spectra from p + p collisions by the average number of binary nucleon-nucleon collisions. The spectra from central collisions are significantly suppressed when compared to the binary-scaled p + p expectation, and also when compared to similarly binary-scaled peripheral collisions, indicating a novel nuclear-medium effect in central nuclear collisions at RHIC energies.
The Λ¯/Λ and Λ¯/K0S production ratios are measured by the LHCb detector from 0.3 nb−1 of pp collisions delivered by the LHC at s√=0.9 TeV and 1.8 nb−1 at s√=7 TeV. Both ratios are presented as a ...function of transverse momentum, p T, and rapidity, y, in the ranges 0.15 < p T < 2.50 GeV/c and 2.0 < y < 4.5. Results at the two energies are in good agreement as a function of rapidity loss, ∆y = y beam − y, and are consistent with previous measurements. The ratio Λ¯/Λ , measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio Λ¯/K0S , measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected.
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