Mon·Mar 18, 2024Monday·March 18, 2024

1. 01*

   Proton Beam Based Production of Positron Emitters by Exploiting the 27Al(p,x)22Na Reaction

   Lisa-Marie Krug · Leon Cryssos · Juergen Bundesmann · Alina Dittwald · Georgios Kourkafas · Andrea Denker · Christoph Hugenschmidt

   Positron annihilation experiments on an laboratory scale depend on the supply and the availability of ${\beta }^{+}$ emitters. Here we present the production of positron sources based on the ${}^{27}$Al(p,x)${}^{22}$Na reaction by irradiation of Al with a 68\,MeV proton beam. We simulated the energy loss, range and radial scattering of the protons in Al in order to design a simple target consisting of a stack of Al discs. Our approach allows (i) the direct use of the Al discs as positron emitters that inherently avoids wet chemical processes as usually applied in commercial production of carrier-free ${}^{22}$Na, (ii) the production of multiple positron sources at once, and (iii) the simple measurement of the depth and lateral distribution of ${}^{22}$Na. We precisely determined the cross section of the ${}^{27}$Al(p,x)${}^{22}$Na reaction which was found to differ from literature values particularly for proton energies between 27 and 40\,MeV. The activity of all nuclides produced (apart from ${}^{22}$Na) was shown to be negligible 15 days after irradiation. The production of radionuclides such as ${}^{48}$Sc, ${}^{54}$Mn and ${}^{56}$Co can be prevented by using Al of a higher purity. The concept presented here can easily be adapted for the production of stronger ${}^{22}$Na sources by increasing the proton current or/and the irradiation time.

   nucl-exphysics.ins-detNucl.Instrum.Meth.B(2024)·2 citations
2. 02*

   Measurement of the 1-jettiness event shape observable in deep-inelastic electron-proton scattering at HERA

   The H1 collaboration: V. Andreev (50) · M. Arratia (34)🇺🇸 · A. Baghdasaryan (46)🇦🇲 · A. Baty (9)🇺🇸 · K. Begzsuren (40)🇲🇳 · A. Bolz (17)🇩🇪 · V. Boudry (30)🇫🇷 · G. Brandt (15)🇩🇪 · D. Britzger (26)🇩🇪 · A. Buniatyan (7)🇬🇧 · L. Bystritskaya (50) · A.J. Campbell (17)🇩🇪 and 136 other authors

   The H1 Collaboration reports the first measurement of the 1-jettiness event shape observable ${\tau }_1^b$ in neutral-current deep-inelastic electron-proton scattering (DIS). The observable ${\tau }_1^b$ is equivalent to a thrust observable defined in the Breit frame. The data sample was collected at the HERA $ep$ collider in the years 2003-2007 with center-of-mass energy of $\sqrt{s}=319\text{GeV}$, corresponding to an integrated luminosity of $351.1{\text{pb}}^{-1}$. Triple differential cross sections are provided as a function of ${\tau }_1^b$, event virtuality $Q^2$, and inelasticity $y$, in the kinematic region $Q^2>150{\text{GeV}}^2$. Single differential cross section are provided as a function of ${\tau }_1^b$ in a limited kinematic range. Double differential cross sections are measured, in contrast, integrated over ${\tau }_1^b$ and represent the inclusive neutral-current DIS cross section measured as a function of $Q^2$ and $y$. The data are compared to a variety of predictions and include classical and modern Monte Carlo event generators, predictions in fixed-order perturbative QCD where calculations up to $\mathcal{O}({\alpha }_s^3)$ are available for ${\tau }_1^b$ or inclusive DIS, and resummed predictions at next-to-leading logarithmic accuracy matched to fixed order predictions at $\mathcal{O}({\alpha }_s^2)$. These comparisons reveal sensitivity of the 1-jettiness observable to QCD parton shower and resummation effects, as well as the modeling of hadronization and fragmentation. Within their range of validity, the fixed-order predictions provide a good description of the data. Monte Carlo event generators are predictive over the full measured range and hence their underlying models and parameters can be constrained by comparing to the presented data.

   ↳ hep-exhep-phnucl-exEPJC(2024)·22 citations
3. 03*

   Measurement of groomed event shape observables in deep-inelastic electron-proton scattering at HERA

   The H1 collaboration: V. Andreev (50) · M. Arratia (34)🇺🇸 · A. Baghdasaryan (46)🇦🇲 · A. Baty (9)🇺🇸 · K. Begzsuren (40)🇲🇳 · A. Bolz (17)🇩🇪 · V. Boudry (30)🇫🇷 · G. Brandt (15)🇩🇪 · D. Britzger (26)🇩🇪 · A. Buniatyan (7)🇬🇧 · L. Bystritskaya (50) · A.J. Campbell (17)🇩🇪 and 135 other authors

   The H1 Collaboration at HERA reports the first measurement of groomed event shape observables in deep inelastic electron-proton scattering (DIS) at $\sqrt{s}=319$ GeV, using data recorded between the years 2003 and 2007 with an integrated luminosity of $351$ pb${}^{-1}$. Event shapes provide incisive probes of perturbative and non-perturbative QCD. Grooming techniques have been used for jet measurements in hadronic collisions; this paper presents the first application of grooming to DIS data. The analysis is carried out in the Breit frame, utilizing the novel Centauro jet clustering algorithm that is designed for DIS event topologies. Events are required to have squared momentum-transfer $Q^2>150$ GeV${}^2$ and inelasticity $0.2<y<0.7$. We report measurements of the production cross section of groomed event 1-jettiness and groomed invariant mass for several choices of grooming parameter. Monte Carlo model calculations and analytic calculations based on Soft Collinear Effective Theory are compared to the measurements.

   ↳ hep-exhep-phnucl-exEPJC(2024)·18 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.