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Do-Won Kim

Publications and source records attributed to Do-Won Kim.

4 recordsLinked to original sources
arXiv2019

Effects of Proton Irradiation on 60 GHz CMOS Transceiver Chip for Multi-Gbps Communication in High-Energy Physics Experiments

This paper presents the experimental results of $17~MeV$ proton irradiation on a $60~GHz$ low power, half-duplex transceiver (TRX) chip implemented in $65~nm$ CMOS technology. It supports short range point-to-point data rate up to $6~Gbps$ by employing on-off keying (OOK). To investigate the irradiation hardness for high energy physics applications, two TRX chips were irradiated with total ionizing doses (TID) of $74~kGy$ and $42~kGy$ and fluence of $1.4~\times$10$^{14}~ N_{eq}/cm^2$ and $0.8~\times$10$^{14}~N_{eq}/cm^2$ for RX and TX modes, respectively. The chips were characterized by pre- and post-irradiation analogue voltage measurements on different circuit blocks as well as through the analysis of wireless transmission parameters like bit error rate (BER), eye diagram, jitter etc. Post-irradiation measurements have shown certain reduction in performance but both TRX chips have been found operational through over the air measurements at $5~Gbps$. Moreover, very small shift in the carrier frequency was observed after the irradiation.

physics.ins-det↗
arXiv2004

Decay Constants of $D_{sJ}^*$(2317) and $D_{sJ}$(2460)

The resonances $D_{sJ}^*$(2317) and $D_{sJ}$(2460) which are considered to be the $(0^+,1^+)$ doublet composed of charm and strange quarks have been discovered recently. Using the method of Rosner which is based on the factorization hypothesis, we calculate the lower bounds of the decay constants of these states from the branching ratios of $B\to D D_{sJ}$ measured by Belle and Babar.Our result shows that the decay constant of $D_{sJ}$(2460) is about twice that of $D_{sJ}^*$(2317) on the contrary to the naive expectation of the heavy quark symmetry which gives their equality. We show that this big deviation originates from the large internal motion of quarks inside these $P$-wave states and that our result is in good accord with the relativistic quark model calculation.

hep-ph↗
arXiv1999

Model Independent Calculation of ${\cal{B}}({\bar{B}}^0\to D^{(*)+} τ^- {\barν})/ {\cal{B}}({\bar{B}}^0\to D^{(*)+} e^- {\barν})$

Using the formulas for the $dΓ/ dq^2$ distribution with non-zero lepton mass and experimentally determined form factors, we calculate the $dΓ(D^{(*)+} l^- {\barν})/ dq^2$ spectra and branching fractions for $l=e$, $μ$ and $τ$. We obtain the results ${\cal{B}}({\bar{B}}^0\rightarrow D^{+} τ^- {\barν})/ {\cal{B}}({\bar{B}}^0\rightarrow D^{+} e^- {\barν})= 0.278^{+0.049}_{-0.035}$ and ${\cal{B}}({\bar{B}}^0\rightarrow D^{*+} τ^- {\barν})/ {\cal{B}}({\bar{B}}^0\rightarrow D^{*+} e^- {\barν})= 0.256^{+0.014}_{-0.013}$ . Since we used the experimentally measured form factors, these results are independent of theoretical models of form factors.

hep-ph↗
arXiv1999

Form Factors in D Meson Decays

We study the $dΓ/ dq^2$ spectra and the branching fractions of the $D$ meson exclusive semileptonic decays with the lepton mass effects into consideration. We investigate their sensitivity to form factor models, and find that the decays to a pseudoscalar meson and a lepton pair are sensitive to the property of the form factor $F_1(q^2)$, and those to a vector meson and a lepton pair to the form factor $A_1(q^2)$. We also analyze the experimental results of the branching fractions $\cal{B} (D^0\to K^- (or π^-) π^+)$ and $\cal{B} (D^0\to K^- (or π^-) e^+ ν)$, and show that it is implied that $F_1(q^2)$ is of dipole type, instead of simple pole type which is commonly assumed.

hep-ph↗