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 TOTEM experiment at the LHC has performed the first measurement at Formula omitted of the Formula omitted parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at ...Formula omitted, obtaining the following results: Formula omitted and Formula omitted, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the Formula omitted measurement, combined with the TOTEM total cross-section measurements in an energy range larger than Formula omitted (from 2.76 to Formula omitted), has implied the exclusion of all the models classified and published by COMPETE. The Formula omitted 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 Formula omitted 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 Formula omitted, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields Formula omitted.
Abstract
The TOTEM experiment at the LHC has performed the first measurement at
$$\sqrt{s} = 13\,\mathrm{TeV}$$
s
=
13
TeV
of the
$$\rho $$
ρ
parameter, the real to imaginary ratio of the nuclear ...elastic scattering amplitude at
$$t=0$$
t
=
0
, obtaining the following results:
$$\rho = 0.09 \pm 0.01$$
ρ
=
0.09
±
0.01
and
$$\rho = 0.10 \pm 0.01$$
ρ
=
0.10
±
0.01
, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the
$$\rho $$
ρ
measurement, combined with the TOTEM total cross-section measurements in an energy range larger than
$$10\,\mathrm{TeV}$$
10
TeV
(from 2.76 to
$$13\,\mathrm{TeV}$$
13
TeV
), has implied the exclusion of all the models classified and published by COMPETE. The
$$\rho $$
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
$$\rho $$
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
$$\sigma _{\mathrm{tot}} = (110.3 \pm 3.5)\,\mathrm{mb}$$
σ
tot
=
(
110.3
±
3.5
)
mb
, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields
$$\sigma _{\mathrm{tot}} = (110.5 \pm 2.4)\,\mathrm{mb}$$
σ
tot
=
(
110.5
±
2.4
)
mb
.
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 σtot=(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 σel=(31.0 ± 1.7) mb and σinel=(79.5 ± 1.8) mb .
The TOTEM collaboration has measured the proton-proton total cross section at Formula omitted with a luminosity-independent method. Using dedicated Formula omitted 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 Formula omitted) 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: Formula omitted and Formula omitted.
Abstract The TOTEM collaboration has measured the proton–proton total cross section at $$\sqrt{s}=13~\hbox {TeV}$$ s=13TeV with a luminosity-independent method. Using dedicated $$\beta ^{*}=90~\hbox ...{m}$$ β∗=90m 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 $$\sigma _\mathrm{tot}=(110.6~\pm ~3.4$$ σtot=(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: $$\sigma _\mathrm{el}=(31.0~\pm ~1.7)~\hbox {mb}$$ σel=(31.0±1.7)mb and $$\sigma _\mathrm{inel}=(79.5~\pm ~1.8)~\hbox {mb}$$ σinel=(79.5±1.8)mb .
Highly integrated multichannel readout electronics is crucial in contemporary particle physics experiments. A novel silicon photomultiplier readout system based on the VMM3a ASIC was developed, for ...the first time exploiting this chip for calorimetric purposes. To extend the dynamic range the signal from each SiPM channel was processed by two electronics channels with different gain. A fully operational prototype system with 256 SiPM readout channels allowed the collection of data from a prototype of the ALICE Forward Hadron Calorimeter (FoCal-H). The design and the test beam results using high energy hadron beams are presented and discussed, confirming the applicability of VMM3a-based solutions for energy measurements in a high rate environment.
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