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5,425
result(s) for
"Zhong, Bo"
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The transverse momentum distribution of hadrons within jets
by
Ringer, Felix
,
Xing, Hongxi
,
Kang, Zhong-Bo
in
Classical and Quantum Gravitation
,
Distribution functions
,
Elementary Particles
2017
A
bstract
We study the transverse momentum distribution of hadrons within jets, where the transverse momentum is defined with respect to the standard jet axis. We consider the case where the jet substructure measurement is performed for an inclusive jet sample
pp
→ jet + X. We demonstrate that this observable provides new opportunities to study transverse momentum dependent fragmentation functions (TMDFFs) which are currently poorly constrained from data, especially for gluons. The factorization of the cross section is obtained within Soft Collinear Effective Theory (SCET), and we show that the relevant TMDFFs are the same as for the more traditional processes semi-inclusive deep inelastic scattering (SIDIS) and electron-positron annihilation. Different than in SIDIS, the observable for the in-jet fragmentation does not depend on TMD parton distribution functions which allows for a cleaner and more direct probe of TMDFFs. We present numerical results and compare to available data from the LHC.
Journal Article
Global analysis of the Sivers functions at NLO+NNLL in QCD
by
Kang, Zhong-Bo
,
Echevarria, Miguel G.
,
Terry, John
in
Asymmetry
,
Bosons
,
Classical and Quantum Gravitation
2021
A
bstract
We perform global fit to the quark Sivers function within the transverse momentum dependent (TMD) factorization formalism in QCD. We simultaneously fit Sivers asymmetry data from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at COMPASS, HERMES, and JLab, from Drell-Yan lepton pair production at COMPASS, and from
W/Z
boson at RHIC. This extraction is performed at next-to-leading order (NLO) and next-to-next-to leading logarithmic (NNLL) accuracy. We find excellent agreement between our extracted asymmetry and the experimental data for SIDIS and Drell-Yan lepton pair production, while tension arises when trying to describe the spin asymmetries of
W/Z
bosons at RHIC. We carefully assess the situation, and we study in details the impact of the RHIC data and their implications through different ways of performing the fit. In addition, we find that the quality of the description of
W/Z
vector boson asymmetry data could be strongly sensitive to the DGLAP evolution of Qiu-Sterman function, besides the usual TMD evolution. We present discussion on this and the implications for measurements of the transverse-spin asymmetries at the future Electron Ion Collider.
Journal Article
The semi-inclusive jet function in SCET and small radius resummation for inclusive jet production
by
Ringer, Felix
,
Kang, Zhong-Bo
,
Vitev, Ivan
in
Classical and Quantum Gravitation
,
Collisions
,
Computational efficiency
2016
A
bstract
We introduce a new kind of jet function: the semi-inclusive jet function
J
i
(
z, ω
J
, μ
), which describes how a parton
i
is transformed into a jet with a jet radius
R
and energy fraction
z
=
ω
J
/ω
, with
ω
J
and
ω
being the large light-cone momentum component of the jet and the corresponding parton
i
that initiates the jet, respectively. Within the framework of Soft Collinear Effective Theory (SCET) we calculate both
J
q
(
z, ω
J
, μ
) and
J
g
(
z, ω
J
, μ
) to the next-to-leading order (NLO) for cone and anti-k
T
algorithms. We demonstrate that the renormalization group (RG) equations for
J
i
(
z, ω
J
, μ
) follow exactly the usual DGLAP evolution, which can be used to perform the ln
R
resummation for
inclusive
jet cross sections with a small jet radius
R
. We clarify the difference between our RG equations for
J
i
(
z, ω
J
, μ
) and those for the so-called unmeasured jet functions
J
i
(
ω
J
, μ
), widely used in SCET for
exclusive
jet production. Finally, we present applications of the new semi-inclusive jet functions to inclusive jet production in
e
+
e
−
and
pp
collisions. We demonstrate that single inclusive jet production in these collisions shares the same short-distance hard functions as single inclusive hadron production, with only the fragmentation functions
D
i
h
(
z
,
μ
) replaced by
J
i
(
z, ω
J
, μ
). This can facilitate more efficient higher-order analytical computations of jet cross sections. We further match our ln
R
resummation at both LL
R
and NLL
R
to fixed NLO results and present the phenomenological implications for single inclusive jet production at the LHC.
Journal Article
The groomed and ungroomed jet mass distribution for inclusive jet production at the LHC
by
Ringer, Felix
,
Kang, Zhong-Bo
,
Lee, Kyle
in
Classical and Quantum Gravitation
,
Elementary Particles
,
High energy physics
2018
A
bstract
We study jet mass distributions measured in the single inclusive jet production in proton-proton collisions
pp
→ jet+
X
at the LHC. We consider both standard ungroomed jets as well as soft drop groomed jets. Within the Soft Collinear Effective Theory (SCET), we establish QCD factorization theorems for both cases and we study their relation. The developed framework allows for the joint resummation of several classes of logarithmic corrections to all orders in the strong coupling constant. For the ungroomed case, we resum logarithms in the jet radius parameter and in the small jet mass. For the groomed case, we resum in addition the logarithms in the soft threshold parameter
z
cut
which is introduced by the soft drop grooming algorithm. In this way, we are able to reliably determine the absolute normalization of the groomed jet mass distribution in proton-proton collisions. All logarithmic corrections are resummed to the next-to-leading logarithmic accuracy. We present numerical results and compare with the available data from the LHC. For both the groomed and ungroomed jet mass distributions we find very good agreement after including non-perturbative corrections.
Journal Article
Jet angularity measurements for single inclusive jet production
by
Ringer, Felix
,
Kang, Zhong-Bo
,
Lee, Kyle
in
Classical and Quantum Gravitation
,
Elementary Particles
,
Field theory
2018
A
bstract
We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter
a
allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.
Journal Article
Washing Away Your Sins: Threatened Morality and Physical Cleansing
2006
Physical cleansing has been a focal element in religious ceremonies for thousands of years. The prevalence of this practice suggests a psychological association between bodily purity and moral purity. In three studies, we explored what we call the \"Macbeth effect\"--that is, a threat to one's moral purity induces the need to cleanse oneself. This effect revealed itself through an increased mental accessibility of cleansing-related concepts, a greater desire for cleansing products, and a greater likelihood of taking antiseptic wipes. Furthermore, we showed that physical cleansing alleviates the upsetting consequences of unethical behavior and reduces threats to one's moral self-image. Daily hygiene routines such as washing hands, as simple and benign as they might seem, can deliver a powerful antidote to threatened morality, enabling people to truly wash away their sins.
Journal Article
Spin asymmetries in electron-jet production at the future electron ion collider
by
Zhao, Fanyi
,
Kang, Zhong-Bo
,
Lee, Kyle
in
Asymmetry
,
Classical and Quantum Gravitation
,
Distribution functions
2021
A
bstract
We study all the possible spin asymmetries that can arise in back-to-back electron-jet production,
ep
→
e
+ jet +
X
, as well as the associated jet fragmentation process,
ep
→
e
+jet(
h
)+
X
, in electron-proton collisions. We derive the factorization formalism for these spin asymmetries and perform the corresponding phenomenology for the kinematics relevant to the future electron ion collider. In the case of unpolarized electron-proton scattering, we also give predictions for azimuthal asymmetries for the HERA experiment. This demonstrates that electron-jet production is an outstanding process for probing unpolarized and polarized transverse momentum dependent parton distribution functions and fragmentation functions.
Journal Article
Jet substructure using semi-inclusive jet functions in SCET
by
Ringer, Felix
,
Kang, Zhong-Bo
,
Vitev, Ivan
in
Classical and Quantum Gravitation
,
Consistency
,
Elementary Particles
2016
A
bstract
We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron
h
is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function
G
i
h
z
=
ω
J
/
ω
,
z
h
=
ω
h
/
ω
J
,
ω
J
,
R
,
μ
, which depends on the jet radius
R
and the large light-cone momenta of the parton ‘
i
’ initiating the jet (
ω
), the jet (
ω
J
), and the hadron
h
(
ω
h
). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function
G
i
h
z
z
h
ω
J
R
μ
are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter
R
up to next-to-leading logarithmic (NLL
R
) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL
R
results for the hadron distribution inside the jet. We present numerical results for
pp
→ (jet
h
)
X
in the new framework, and find excellent agreement with existing LHC experimental data.
Journal Article
Do Green Products Make Us Better People?
2010
Consumer choices reflect not only price and quality preferences but also social and moral values, as witnessed in the remarkable growth of the global market for organic and environmentally friendly products. Building on recent research on behavioral priming and moral regulation, we found that mere exposure to green products and the purchase of such products lead to markedly different behavioral consequences. In line with the halo associated with green consumerism, results showed that people act more altruistically after mere exposure to green products than after mere exposure to conventional products. However, people act less altruistically and are more likely to cheat and steal after purchasing green products than after purchasing conventional products. Together, our studies show that consumption is connected to social and ethical behaviors more broadly across domains than previously thought.
Journal Article
QCD resummation on single hadron transverse momentum distribution with the thrust axis
by
Kang, Zhong-Bo
,
Zhao, Fanyi
,
Shao, Ding Yu
in
Classical and Quantum Gravitation
,
Effective Field Theories
,
Elementary Particles
2020
A
bstract
We derive the transverse momentum dependent (TMD) factorization and resummation formula of the unpolarized transverse momentum distribution (
j
T
) for the single hadron production with the thrust axis in an electron-positron collision. Two different kinematic regions are considered, including small transverse momentum limit
j
T
«
Q
, and joint transverse momentum and threshold limit
j
T
«
Q
(1
− z
h
) «
Q
, where
Q
and
z
h
are the hard scattering energy and the observed hadron momentum fraction. Using effective theory methods, we resum logarithms ln(
Q/j
T
) and ln(1
− z
h
) to all orders. In the end, we present the differential cross sections and Gaussian widths calculated for the inclusive charged pion production and find that our results are consistent with the measurements reported by the Belle collaboration.
Journal Article