1,020 research outputs found
Pileup subtraction using jet areas
One of the major challenges for the LHC will be to extract precise
information from hadronic final states in the presence of the large number of
additional soft pp collisions, pileup, that occur simultaneously with any hard
interaction in high luminosity runs. We propose a novel technique, based on jet
areas, that provides jet-by-jet corrections for pileup and underlying-event
effects. It is data driven, does not depend on Monte Carlo modelling and can be
used with any jet algorithm for which a jet area can be sensibly defined. We
illustrate its effectiveness for some key processes and find that it can be
applied also in the context of the Tevatron, low-luminosity LHC and LHC
heavy-ion collisions.Comment: 12 pages, 7 figures. Revised version with many changes and additions,
small and larger. No changes in conclusions. Version published in Physics
Letters
Probabilistic Particle Flow Algorithm for High Occupancy Environment
Algorithms based on the particle flow approach are becoming increasingly
utilized in collider experiments due to their superior jet energy and missing
energy resolution compared to the traditional calorimeter-based measurements.
Such methods have been shown to work well in environments with low occupancy of
particles per unit of calorimeter granularity. However, at higher instantaneous
luminosity or in detectors with coarse calorimeter segmentation, the overlaps
of calorimeter energy deposits from charged and neutral particles significantly
complicate particle energy reconstruction, reducing the overall energy
resolution of the method. We present a technique designed to resolve
overlapping energy depositions of spatially close particles using a
statistically consistent probabilistic procedure. The technique is nearly free
of ad-hoc corrections, improves energy resolution, and provides new important
handles that can improve the sensitivity of physics analyses: the uncertainty
of the jet energy on an event-by-event basis and the estimate of the
probability of a given particle hypothesis for a given detector response. When
applied to the reconstruction of hadronic jets produced in the decays of tau
leptons using the CDF-II detector at Fermilab, the method has demonstrated
reliable and robust performance.Comment: Accepted by Nuclear Instruments and Methods
Independent measurement of the top quark mass and the light- and bottom-jet energy scales at hadron colliders
A method for the simultaneous determination of the energy scales for b-quark
jets and light jets, the jet energy resolution, and the top quark mass at
hadron colliders is presented. The method exploits the unique kinematics of
events with top-antitop pair production, where one of the top quarks involves a
leptonic and one a hadronic W boson decay. The paper shows a feasibility study
of how this simultaneous measurement can be performed at the upcoming LHC
experiments ATLAS and CMS.Comment: 10 pages, 5 figure
B physics at CDF - the Beauty of hadron collisions
The CDF experiment at the Tevatron p-pbar collider established that extensive
and detailed exploration of the b-quark dynamics is possible in hadron
collisions, with results competitive and supplementary to those from e+e-
colliders. This provides an unique, rich, and highly rewarding program that is
currently reaching full maturity. I report a few recent world-leading results
on rare decays, CP-violation in Bs mixing, and b-> s penguin decays.Comment: 6 pages, 5 figures. Write-up of the proceedings of the "Third
Workshop on Theory, Phenomenology and Experiments in Heavy Flavour Physics"
(Capri2010
B(Ds^+ -> l^+ nu) and the Decay Constant f_(D_s^+)
I report final CLEO-c results on the purely leptonic decays of the D_s^+ ->
l^+ nu, for the cases when l^+ is a mu^+ or tau^+, when it decays into pi^+
anti-nu, using 314/pb of data at 4.170 GeV. I also include preliminary results
from the tau^+ -> e^+ nu anti-nu channel using 195/pb. Combining both we
measure f_{D_s}= 275 +/- 10 +/- 5 MeV, and f_{D_s^+}/{f_{D^+}=1.24 +/- 0.10 =/-
0.03 .Comment: Presented at "The 2007 Europhysics Conference on High Energy
Physics," Manchester, England, 19-25 July 2007, to appear in the proceedings.
Three pages, 1 figur
In Pursuit of New Physics in the B System
The B-meson system offers interesting probes for the search of physics beyond
the Standard Model. After addressing possible signals of new-physics
contributions to the B -> phi K and B -> pi K decay amplitudes, we focus on the
data for B^0_q-\bar B^0_q mixing (q = d, s), giving a critical discussion of
their interpretation in terms of model-independent new-physics parameters. We
address, in particular, the impact of the uncertainties of the relevant input
parameters, discuss benchmarks for future precision measurements at the LHC,
and explore the prospects for new CP-violating effects in the B_s-meson system,
which could be detected at the LHC.Comment: 8 pages, 7 figures, invited talk at the 1st Workshop on Theory,
Phenomenology and Experiments in Heavy Flavour Physics, Anacapri, Capri,
Italy, 29-31 May 2006, to appear in the Proceeding
Jets in Hadron-Hadron Collisions
In this article, we review some of the complexities of jet algorithms and of
the resultant comparisons of data to theory. We review the extensive experience
with jet measurements at the Tevatron, the extrapolation of this acquired
wisdom to the LHC and the differences between the Tevatron and LHC
environments. We also describe a framework (SpartyJet) for the convenient
comparison of results using different jet algorithms.Comment: 68 pages, 54 figure
Some Phenomenologies of Unparticle Physics
Fermionic unparticles are introduced and their basic properties are
discussed. Some phenomenologies related are exploited, such as their effects on
charged Higgs boson decays and anomalous magnetic moments of leptons. Also, it
has been found that measurements of mixing could yield
interesting constraints on couplings between unparticle operators and standard
model fields.Comment: Version to appear in Phys. Letts. B. 9 pages, 3 figure
Review of Top Quark Physics Results
As the heaviest known fundamental particle, the top quark has taken a central
role in the study of fundamental interactions. Production of top quarks in
pairs provides an important probe of strong interactions. The top quark mass is
a key fundamental parameter which places a valuable constraint on the Higgs
boson mass and electroweak symmetry breaking. Observations of the relative
rates and kinematics of top quark final states constrain potential new physics.
In many cases, the tests available with study of the top quark are both
critical and unique. Large increases in data samples from the Fermilab Tevatron
have been coupled with major improvements in experimental techniques to produce
many new precision measurements of the top quark. The first direct evidence for
electroweak production of top quarks has been obtained, with a resulting direct
determination of . Several of the properties of the top quark have been
measured. Progress has also been made in obtaining improved limits on potential
anomalous production and decay mechanisms. This review presents an overview of
recent theoretical and experimental developments in this field. We also provide
a brief discussion of the implications for further efforts.Comment: 119 pages, 55 figure
Pilipinx Radical Imagination: Healing and Visioning in our Process of Becoming
There are estimated 10.4 million Filipinos living or working abroad primarily in the Middle East, Europe, Canada, and the United States searching for a better life for themselves and their families (Commission on Filipino Overseas, 2013). Due to economic motivation, assimilating to the host country\u27s culture, values, and traditions is an act of survival. While the majority of the research has focused on the domestic workers’ experience, rarely has there been a study focusing on Filipinos in the diaspora positive contributions to the host country and their Pilipinx Radical Imagination. As a result, the purpose of this qualitative study is to explore diasporic Filipinos’ current lived experiences and visioning for their communities. This study focuses on eight self identified Filipino/a/x/@, Pilipino/a/x/@ or Pin@y contributors from The Pilipinx Radical Imagination Reader (Nievera-Lozano & Santa Ana, 2018). This study utilizes Transcendent Resistance, a newly introduced framework, and FilCrit pedagogy and to examine their lived experiences and interview them with a culturally humble data collection methodology, kuwentuhan, sharing stories, (Jocson, 2008). Analysis of the data demonstrated three themes: (1) identity is culturally fluid; (2) transcendent love is at the heart of their love for themselves and their communities; (3) and healing and visioning. Further research is needed to document the positive contributions of Filipinos in the diaspora, complexities and multiplicities of Filipinos in the diaspora, community kuwentuhans as space for healing and visioning, and further development of the Pilipinx Radical Imagination
- …