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"Mass (Physics) Measurement."
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Word problems : mass and volume
\"Word Problems: Mass and Volume uses an engaging narrative and authentic, real-world problems to teach readers strategies to solve one-step word problems involving mass and volume. The text models the problem-solving process for readers and provides hands-on opportunities for readers to apply their own problem-solving skills. Readers will discover that there is often more than one way to solve a problem\"-- Provided by publisher.
Book
Double Chooz θ13 measurement via total neutron capture detection
Neutrinos were assumed to be massless particles until the discovery of the neutrino oscillation process. This phenomenon indicates that the neutrinos have non-zero masses and the mass eigenstates (
ν
1
,
ν
2
,
ν
3
) are mixtures of their flavour eigenstates (
ν
e
,
ν
μ
,
ν
τ
). The oscillations between different flavour eigenstates are described by three mixing angles (
θ
12
,
θ
23
,
θ
13
), two differences of the squared neutrino masses of the
ν
2
/
ν
1
and
ν
3
/
ν
1
pairs and a charge conjugation parity symmetry violating phase
δ
CP
. The Double Chooz experiment, located near the Chooz Electricité de France reactors, measures the oscillation parameter
θ
13
using reactor neutrinos. Here, the Double Chooz collaboration reports the measurement of the mixing angle
θ
13
with the new total neutron capture detection technique from the full data set, yielding sin
2
(2
θ
13
) = 0.105 ± 0.014. This measurement exploits the multidetector configuration, the isoflux baseline and data recorded when the reactors were switched off. In addition to the neutrino mixing angle measurement, Double Chooz provides a precise measurement of the reactor neutrino flux, given by the mean cross-section per fission 〈
σ
f
〉 = (5.71 ± 0.06) × 10
−43
cm
2
per fission, and reports an empirical model of the distortion in the reactor neutrino spectrum.
The Double Chooz collaboration reports the neutrino oscillation parameter
θ
13
from a measurement of the disappearance of reactor anti-electron neutrinos with the total neutron capture technique.
Journal Article
The last complex WIMPs standing
We continue the study of weakly interacting massive particles (WIMP) started in Bottaro et al. (Eur Phys J C 82:31, 2022), focusing on a single complex electroweak n-plet with non-zero hypercharge added to the Standard Model. The minimal splitting between the Dark Matter and its electroweak neutral partner required to circumvent direct detection constraints allows only multiplets with hypercharge smaller or equal to 1. We compute for the first time all the calculable WIMP masses up to the largest multiplet allowed by perturbative unitarity. For the minimal allowed splitting, most of these multiplets can be fully probed at future large-exposure direct detection experiments, with the notable exception of the doublet with hypercharge 1/2. We show how a future muon collider can fully explore the parameter space of the complex doublet combining missing mass, displaced track and long-lived track searches. In the same spirit, we study how a future muon collider can probe the parameter space of complex WIMPs in regions where the direct detection cross section drops below the neutrino floor. Finally, we comment on how precision observables can provide additional constraints on complex WIMPs.
Journal Article
Uncertainties in WIMP dark matter scattering revisited
We revisit the uncertainties in the calculation of spin-independent scattering matrix elements for the scattering of WIMP dark matter particles on nuclear matter. In addition to discussing the uncertainties due to limitations in our knowledge of the nucleonic matrix elements of the light quark scalar densities \\[\\langle N |{{{\\bar{u}}} u, {{{\\bar{d}}} d, {{{\\bar{s}}} s| N \\rangle \\], we also discuss the importances of heavy quark scalar densities \\[\\langle N |{{{\\bar{c}}} c, {{{\\bar{b}}} b, {{{\\bar{t}}} t| N \\rangle \\], and comment on uncertainties in quark mass ratios. We analyze estimates of the light-quark densities made over the past decade using lattice calculations and/or phenomenological inputs. We find an uncertainty in the combination \\[\\langle N |{{{\\bar{u}}} u + {{{\\bar{d}}} d | N \\rangle \\] that is larger than has been assumed in some phenomenological analyses, and a range of \\[\\langle N |{{{\\bar{s}}} s| N \\rangle \\] that is smaller but compatible with earlier estimates. We also analyze the importance of the \\[{{{\\mathcal {O}}}(\\alpha _s^3)\\] calculations of the heavy-quark matrix elements that are now available, which provide an important refinement of the calculation of the spin-independent scattering cross section. We use for illustration a benchmark CMSSM point in the focus-point region that is compatible with the limits from LHC and other searches.
Journal Article
Open-charm tetraquark Xc and open-bottom tetraquark Xb
Motivated by the LHCb observation of exotic states
X
0
,
1
(
2900
)
with four open quark flavors in the
D
-
K
+
invariant mass distribution in the decay channel
B
±
→
D
+
D
-
K
±
, we study the spectrum and decay properties of the open charm tetraquarks. Using the two-body chromomagnetic interactions, we find that the two newly observed states can be interpreted as a radial excited tetraquark with
J
P
=
0
+
and an orbitally excited tetraquark with
J
P
=
1
-
, respectively. We then explore the mass and decays of the other flavor-open tetraquarks made of
s
u
d
¯
c
¯
and
d
s
u
¯
c
¯
, which are in the
6
¯
or 15 representation of the flavor SU(3) group. We point that these two states can be found through the decays:
X
d
s
u
¯
c
¯
(
′
)
→
(
D
-
K
-
,
D
s
-
π
-
)
, and
X
s
u
d
¯
c
¯
(
′
)
→
D
s
-
π
+
. We also apply our analysis to open bottom tetraquark
X
b
and predict their masses. The open-flavored
X
b
can be discovered through the following decays:
X
u
d
s
¯
b
¯
→
B
0
K
+
,
X
d
s
u
¯
b
¯
(
′
)
→
(
B
0
K
-
,
B
s
0
π
-
)
, and
X
s
u
d
¯
b
¯
(
′
)
→
B
s
0
π
+
.
Journal Article
Multiplicity dependence of π, K, and p production in pp collisions at s=13 TeV
This paper presents the measurements of
π
±
,
K
±
,
p
and
p
¯
transverse momentum (
p
T
) spectra as a function of charged-particle multiplicity density in proton–proton (pp) collisions at
s
=
13
TeV
with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a
p
T
range from 0.1 to 20
GeV
/
c
and are done in the rapidity interval
|
y
|
<
0.5
. The
p
T
-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at
s
=
7
TeV
, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the
p
T
-integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multi-strange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.
Journal Article
Constraints on the off-shell Higgs boson signal strength in the high-mass ZZ and WW final states with the ATLAS detector
Measurements of the
ZZ
and
WW
final states in the mass range above the
2
m
Z
and
2
m
W
thresholds provide a unique opportunity to measure the off-shell coupling strength of the Higgs boson. This paper presents constraints on the off-shell Higgs boson event yields normalised to the Standard Model prediction (signal strength) in the
Z
Z
→
4
ℓ
,
Z
Z
→
2
ℓ
2
ν
and
W
W
→
e
ν
μ
ν
final states. The result is based on
pp
collision data collected by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 20.3 fb
-
1
at a collision energy of
s
=
8
TeV. Using the
C
L
s
method, the observed 95
%
confidence level (CL) upper limit on the off-shell signal strength is in the range 5.1–8.6, with an expected range of 6.7–11.0. In each case the range is determined by varying the unknown
g
g
→
Z
Z
and
g
g
→
W
W
background K-factor from higher-order quantum chromodynamics corrections between half and twice the value of the known signal K-factor. Assuming the relevant Higgs boson couplings are independent of the energy scale of the Higgs boson production, a combination with the on-shell measurements yields an observed (expected) 95
%
CL upper limit on
Γ
H
/
Γ
H
SM
in the range 4.5–7.5 (6.5–11.2) using the same variations of the background K-factor. Assuming that the unknown
g
g
→
V
V
background K-factor is equal to the signal K-factor, this translates into an observed (expected) 95
%
CL upper limit on the Higgs boson total width of 22.7 (33.0) MeV.
Journal Article
Precise Q value determinations for forbidden and low energy β-decays using Penning trap mass spectrometry
Nuclear
β
-decay provides a laboratory for investigating weak decays occurring inside the nuclear medium. This provides information on the resulting subtle nuclear and atomic effects, and on the underlying interaction and the properties of the particles that are involved, particularly of the neutrino. The Q value of the decay corresponds to the energy equivalent of the mass difference between parent and daughter atoms, and can be precisely and accurately measured using Penning trap mass spectrometry. In this paper we discuss Penning trap Q value measurements for forbidden
β
-decays of long-lived primordial nuclides, and for a subset of
β
-unstable nuclides that could potentially undergo a very low energy decay to an excited state in the daughter nucleus. We discuss applications of these measurements to tests of systematics in detectors that perform precise
β
-spectrum measurements, as inputs for theoretical shape factor, electron branching ratio and half-life calculations, and to identify nuclides that could serve as new candidates in direct neutrino mass determination experiments.
Journal Article
Emergence of Hadron Mass and Structure
Visible matter is characterised by a single mass scale; namely, the proton mass. The proton’s existence and structure are supposed to be described by quantum chromodynamics (QCD); yet, absent Higgs boson couplings, chromodynamics is scale-invariant. Thus, if the Standard Model is truly a part of the theory of Nature, then the proton mass is an emergent feature of QCD; and emergent hadron mass (EHM) must provide the basic link between theory and observation. Nonperturbative tools are necessary if such connections are to be made; and in this context, we sketch recent progress in the application of continuum Schwinger function methods to an array of related problems in hadron and particle physics. Special emphasis is given to the three pillars of EHM—namely, the running gluon mass, process-independent effective charge, and running quark mass; their role in stabilising QCD; and their measurable expressions in a diverse array of observables.
Journal Article
Precision mass measurement of lightweight self-conjugate nucleus 80Zr
Protons and neutrons in the atomic nucleus move in shells analogous to the electronic shell structures of atoms. The nuclear shell structure varies as a result of changes in the nuclear mean field with the number of neutrons N and protons Z, and these variations can be probed by measuring the mass differences between nuclei. The N = Z = 40 self-conjugate nucleus 80Zr is of particular interest, as its proton and neutron shell structures are expected to be very similar, and its ground state is highly deformed. Here we provide evidence for the existence of a deformed double-shell closure in 80Zr through high-precision Penning trap mass measurements of 80–83Zr. Our mass values show that 80Zr is substantially lighter, and thus more strongly bound than predicted. This can be attributed to the deformed shell closure at N = Z = 40 and the large Wigner energy. A statistical Bayesian-model mixing analysis employing several global nuclear mass models demonstrates difficulties with reproducing the observed mass anomaly using current theory.High-precision mass measurements of exotic zirconium nuclei are reported, and reveal a double-shell closure for the deformed nucleus 80Zr, which is more strongly bound than previously thought.
Journal Article