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 collaboration has measured the elastic proton-proton differential cross section
d
σ
/
d
t
at
s
=
13
TeV LHC energy using dedicated
β
∗
=
90
m beam optics. The Roman Pot detectors were ...inserted to 10
σ
distance from the LHC beam, which allowed the measurement of the range 0.04 GeV
2
; 4 GeV
2
in four-momentum transfer squared |
t
|. The efficient data acquisition allowed to collect about 10
9
elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-|
t
| tail. The average nuclear slope has been found to be
B
=
(
20.40
±
0
.
002
stat
±
0
.
01
syst
)
GeV
-
2
in the |
t
|-range 0.04–0.2 GeV
2
. The dip position is
|
t
dip
|
=
(
0.47
±
0
.
004
stat
±
0
.
01
syst
)
GeV
2
. The differential cross section ratio at the bump vs. at the dip
R
=
1.77
±
0
.
01
stat
has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.
A reduction of the mass of the η' (958) meson may indicate the restoration of the UA(1) symmetry in a hot and dense hadronic matter, corresponding to the return of the 9th, "prodigal" Goldstone ...boson. We report on an analysis of a combined PHENIX and STAR data set on the intercept parameter of the two-pion Bose-Einstein correlation functions, as measuremed in √sNN = 200 GeV Au+Au collisions at RHIC. To describe this combined PHENIX and STAR dataset, an in-medium η' mass reduction of at least 200 MeV is needed, at the 99.9 % confidence level in a broad model class of resonance multiplicities. Energy, system size and centrality dependence of the observed effect is also discussed.
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 first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with a center-of-mass energy of sqrts=7 TeV. By utilizing ...the very forward TOTEM tracking detectors T1 and T2, which extend up to |η|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we determined the cross section σDD=(116±25) μb for events where both diffractive systems have 4.7<|η|min<6.5.
Abstract
The proton–proton elastic differential cross section
$${\mathrm{d}}\sigma /{\mathrm{d}}t$$
d
σ
/
d
t
has been measured by the TOTEM experiment at
$$\sqrt{s}=2.76\hbox { TeV}$$
s
=
2.76
TeV
...energy with
$$\beta ^{*}=11\hbox { m}$$
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
$$0.74\hbox { GeV}^{2}$$
0.74
GeV
2
. The differential cross-section can be described with an exponential in the |
t
|-range between 0.36 and
$$0.54\hbox { GeV}^{2}$$
0.54
GeV
2
, followed by a diffractive minimum (dip) at
$$|t_{\mathrm{dip}}|=(0.61\pm 0.03)\hbox { GeV}^{2}$$
|
t
dip
|
=
(
0.61
±
0.03
)
GeV
2
and a subsequent maximum (bump). The ratio of the
$${\mathrm{d}}\sigma /{\mathrm{d}}t$$
d
σ
/
d
t
at the bump and at the dip is
$$1.7\pm 0.2$$
1.7
±
0.2
. When compared to the proton–antiproton measurement of the D0 experiment at
$$\sqrt{s} = 1.96\hbox { TeV}$$
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.
Abstract The proton–proton elastic differential cross section $${\mathrm{d}}\sigma /{\mathrm{d}}t$$ dσ/dt has been measured by the TOTEM experiment at $$\sqrt{s}=2.76\hbox { TeV}$$ s=2.76TeV energy ...with $$\beta ^{*}=11\hbox { m}$$ β∗=11m 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 $$0.74\hbox { GeV}^{2}$$ 0.74GeV2 . The differential cross-section can be described with an exponential in the |t|-range between 0.36 and $$0.54\hbox { GeV}^{2}$$ 0.54GeV2 , followed by a diffractive minimum (dip) at $$|t_{\mathrm{dip}}|=(0.61\pm 0.03)\hbox { GeV}^{2}$$ |tdip|=(0.61±0.03)GeV2 and a subsequent maximum (bump). The ratio of the $${\mathrm{d}}\sigma /{\mathrm{d}}t$$ dσ/dt at the bump and at the dip is $$1.7\pm 0.2$$ 1.7±0.2 . When compared to the proton–antiproton measurement of the D0 experiment at $$\sqrt{s} = 1.96\hbox { TeV}$$ s=1.96TeV , 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.
The TOTEM collaboration has measured the elastic proton-proton differential cross section Formula omitted at Formula omitted TeV LHC energy using dedicated Formula omitted m beam optics. The Roman ...Pot detectors were inserted to 10 Formula omitted distance from the LHC beam, which allowed the measurement of the range 0.04 GeV Formula omitted; 4 GeV Formula omitted Formula omitted in four-momentum transfer squared |t|. The efficient data acquisition allowed to collect about 10 Formula omitted elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-|t| tail. The average nuclear slope has been found to be Formula omittedGeV Formula omitted in the |t|-range 0.04-0.2 GeV Formula omitted. The dip position is Formula omittedGeV Formula omitted. The differential cross section ratio at the bump vs. at the dip Formula omitted has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.
Abstract The TOTEM collaboration has measured the elastic proton-proton differential cross section $$\mathrm{d}\sigma /\mathrm{d}t$$ dσ/dt at $$\sqrt{s}=13$$ s=13 TeV LHC energy using dedicated ...$$\beta ^{*}=90$$ β∗=90 m beam optics. The Roman Pot detectors were inserted to 10$$\sigma $$ σ distance from the LHC beam, which allowed the measurement of the range 0.04 GeV$$^{2}$$ 2 ; 4 GeV$$^{2}$$ 2 $$$$ in four-momentum transfer squared |t|. The efficient data acquisition allowed to collect about 10$$^{9}$$ 9 elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-|t| tail. The average nuclear slope has been found to be $$B=(20.40 \pm 0.002^{\mathrm{stat}} \pm 0.01^{\mathrm{syst}})~$$ B=(20.40±0.002stat±0.01syst) GeV$$^{-2}$$ -2 in the |t|-range 0.04–0.2 GeV$$^{2}$$ 2 . The dip position is $$|t_{\mathrm{dip}}|=(0.47 \pm 0.004^{\mathrm{stat}} \pm 0.01^{\mathrm{syst}})~$$ |tdip|=(0.47±0.004stat±0.01syst) GeV$$^{2}$$ 2 . The differential cross section ratio at the bump vs. at the dip $$R=1.77\pm 0.01^{\mathrm{stat}}$$ R=1.77±0.01stat has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.
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