The TOTEM collaboration has measured the proton-proton total cross section at √s=8 TeV using a luminosity-independent method. In LHC fills with dedicated beam optics, the Roman pots have been ...inserted very close to the beam allowing the detection of ~90% of the nuclear elastic scattering events. Simultaneously the inelastic scattering rate has been measured by the T1 and T2 telescopes. By applying the optical theorem, the total proton-proton cross section of (101.7±2.9) mb has been determined, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: σ(el)=(27.1±1.4) mb; σ(inel)=(74.7±1.7) mb.
The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton–proton scattering at
s
=
8
TeV
in the squared four-momentum transfer range
0.2
GeV
2
<
|
t
|
<
...1.9
GeV
2
. This interval includes the structure with a diffractive minimum (“dip”) and a secondary maximum (“bump”) that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for
s
=
8
TeV
yields the positions,
|
t
|
dip
=
(
0.521
±
0.007
)
GeV
2
and
|
t
|
bump
=
(
0.695
±
0.026
)
GeV
2
, as well as the cross-section values,
d
σ
/
d
t
dip
=
(
15.1
±
2.5
)
μ
b
/
GeV
2
and
d
σ
/
d
t
bump
=
(
29.7
±
1.8
)
μ
b
/
GeV
2
, for the dip and the bump, respectively.
Abstract
The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton–proton scattering at
$$\sqrt{s} = 8\,\mathrm{TeV}$$
s
=
8
TeV
in the squared ...four-momentum transfer range
$$0.2\,\mathrm{GeV^{2}}< |t| < 1.9\,\mathrm{GeV^{2}}$$
0.2
GeV
2
<
|
t
|
<
1.9
GeV
2
. This interval includes the structure with a diffractive minimum (“dip”) and a secondary maximum (“bump”) that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for
$$\sqrt{s} = 8\,\mathrm{TeV}$$
s
=
8
TeV
yields the positions,
$$|t|_{\mathrm{dip}} = (0.521 \pm 0.007)\,\mathrm{GeV^2}$$
|
t
|
dip
=
(
0.521
±
0.007
)
GeV
2
and
$$|t|_{\mathrm{bump}} = (0.695 \pm 0.026)\,\mathrm{GeV^2}$$
|
t
|
bump
=
(
0.695
±
0.026
)
GeV
2
, as well as the cross-section values,
$$\left. {\mathrm{d}\sigma /\mathrm{d}t}\right| _{\mathrm{dip}} = (15.1 \pm 2.5)\,\mathrm{{\mu b/GeV^2}}$$
d
σ
/
d
t
dip
=
(
15.1
±
2.5
)
μ
b
/
GeV
2
and
$$\left. {\mathrm{d}\sigma /\mathrm{d}t}\right| _{\mathrm{bump}} = (29.7 \pm 1.8)\,\mathrm{{\mu b/GeV^2}}$$
d
σ
/
d
t
bump
=
(
29.7
±
1.8
)
μ
b
/
GeV
2
, for the dip and the bump, respectively.
The proton–proton elastic differential cross section
d
σ
/
d
t
has been measured by the TOTEM experiment at
s
=
2.76
TeV
energy with
β
∗
=
11
m
beam optics. The Roman Pots were inserted to 13 times ...the transverse beam size from the beam, which allowed to measure the differential cross-section of elastic scattering in a range of the squared four-momentum transfer (|
t
|) from 0.36 to
0.74
GeV
2
. The differential cross-section can be described with an exponential in the |
t
|-range between 0.36 and
0.54
GeV
2
, followed by a diffractive minimum (dip) at
|
t
dip
|
=
(
0.61
±
0.03
)
GeV
2
and a subsequent maximum (bump). The ratio of the
d
σ
/
d
t
at the bump and at the dip is
1.7
±
0.2
. When compared to the proton–antiproton measurement of the D0 experiment at
s
=
1.96
TeV
, a significant difference can be observed. Under the condition that the effects due to the energy difference between TOTEM and D0 can be neglected, the result provides evidence for the exchange of a colourless C-odd three-gluon compound state in the
t
-channel of the proton–proton and proton–antiproton elastic scattering.
Background
Spontaneous coronary artery dissection (SCAD) is often treated conservatively due to revascularization risks. Yet, an important number of SCAD patients have high acuity characteristics ...necessitating revascularization, with uncertain long‐term outcomes.
Objectives
Document revascularization utilization and long‐term outcomes in high acuity SCAD.
Methods
Prospective/retrospective analysis of consecutive patients with acute myocardial infarction (AMI) due to first SCAD event presenting directly to the Minneapolis Heart Institute 2002−2021, median follow‐up 3.8 years.
Results
Among 139 patients (age 49 ± 12 years, 96% female), revascularization was performed in 60 (43%), utilizing percutaneous coronary intervention (PCI) (n = 56, successful in 80%) or coronary artery bypass graft (n = 4). In the entire cohort, 90 (65%) unique patients had one or more high acuity characteristic: ST‐elevation (38%), proximal dissection (38%), cardiogenic shock (6.5%), cardiac arrest (9.4%), left main dissection (6.5%), peripartum dissection (7.2%). High acuity patients accounted for 51 of 60 (85%) revascularizations. Revascularization rates were: ST‐elevation (60%), proximal dissection (62%), cardiogenic shock (89%), cardiac arrest (62%), left main dissection (100%), peripartum dissection (70%). Survival was 97% (revascularized) vs 100% (nonrevascularized); p = 0.2. Adverse outcomes (revascularized vs. nonrevascularized) included recurrent AMI:16.7% versus 8.9%; p = 0.2, SCAD recurrence: 13.3% versus 6.3%; p = 0.1, stroke: 5% versus 2.5%; p = 0.44, implantable cardioverter‐defibrillator: 6.7% versus 6.3%; p > 0.9. Reintervention was necessary in 21% of PCI‐treated patients.
Conclusions
High‐acuity characteristics were present in nearly two‐thirds of this SCAD cohort; the vast majority of revascularizations were performed in high‐acuity patients. Despite high acuity, long‐term survival was favorable in revascularized patients.
The TOTEM collaboration has measured the proton–proton total cross section at
s
=
13
TeV
with a luminosity-independent method. Using dedicated
β
∗
=
90
m
beam optics, the Roman Pots were inserted ...very close to the beam. The inelastic scattering rate has been measured by the T1 and T2 telescopes during the same LHC fill. After applying the optical theorem the total proton–proton cross section is
σ
tot
=
(
110.6
±
3.4
) mb, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections:
σ
el
=
(
31.0
±
1.7
)
mb
and
σ
inel
=
(
79.5
±
1.8
)
mb
.
The TOTEM experiment at the LHC has performed the first measurement at
s
=
13
TeV
of the
ρ
parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at
t
=
0
, obtaining the ...following results:
ρ
=
0.09
±
0.01
and
ρ
=
0.10
±
0.01
, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the
ρ
measurement, combined with the TOTEM total cross-section measurements in an energy range larger than
10
TeV
(from 2.76 to
13
TeV
), has implied the exclusion of all the models classified and published by COMPETE. The
ρ
results obtained by TOTEM are compatible with the predictions, from other theoretical models both in the Regge-like framework and in the QCD framework, of a crossing-odd colourless 3-gluon compound state exchange in the
t
-channel of the proton–proton elastic scattering. On the contrary, if shown that the crossing-odd 3-gluon compound state
t
-channel exchange is not of importance for the description of elastic scattering, the
ρ
value determined by TOTEM would represent a first evidence of a slowing down of the total cross-section growth at higher energies. The very low-|
t
| reach allowed also to determine the absolute normalisation using the Coulomb amplitude for the first time at the LHC and obtain a new total proton–proton cross-section measurement
σ
tot
=
(
110.3
±
3.5
)
mb
, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields
σ
tot
=
(
110.5
±
2.4
)
mb
.
Status of the TOTEM experiment at LHC Baechler, J.; Antchev, G.; Aspell, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Volume:
718
Journal Article
Peer reviewed
The TOTEM experiment is dedicated to the measurement of the total proton–proton cross-section with the luminosity-independent method and the study of elastic and diffractive scattering processes. Two ...tracking telescopes, T1 and T2, integrated in the CMS detector, cover the pseudo-rapidity region between 3.1 and 6.5 on both sides of the interaction point IP5. The Roman Pot (RP) stations are located at distances of ±147m and ±220m with respect to the interaction point to measure the very forward scattered protons at very small angles. During the LHC technical stop in winter 2010/2011, the TOTEM experiment was completed with the installation of the T1 telescope and the RP stations at ±147m. In 2011, the LHC machine provided special optics with the large ß⁎=90m, allowing TOTEM to measure the elastic scattering differential cross-section, down to the four-momentum transfer squared |t|=2×10−2GeV2. Using the optical theorem and extrapolation of the differential cross-section to t=0 (optical point), the total p–p cross-section at the LHC energy of s=7TeV could be computed for the first time. Furthermore we measured with standard LHC beam optics and the energy of s=7TeV the forward charged particle pseudorapidity density dn/dη in the range of 5.3<|η|<6.4. The status of the experiment, the performance of the detectors with emphasis on the RPs are described and the first physics results are presented.
The TOTEM collaboration at the CERN LHC has measured the differential cross-section of elastic proton-proton scattering at Formula omitted in the squared four-momentum transfer range Formula omitted. ...This interval includes the structure with a diffractive minimum ("dip") and a secondary maximum ("bump") that has also been observed at all other LHC energies, where measurements were made. A detailed characterisation of this structure for Formula omitted yields the positions, Formula omitted and Formula omitted, as well as the cross-section values, Formula omitted and Formula omitted, for the dip and the bump, respectively.
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